12. Solutions12. Solutions

ContentsContents

1. Solubility1. Solubility2. Some Solvents for Liquid Preparat2. Some Solvents for Liquid Preparat

ionsions3. Preparation of Solutions3. Preparation of Solutions4. Oral Solutions and Preparations f4. Oral Solutions and Preparations f

or Oral Solutionor Oral Solution5. Syrups5. Syrups

6. Elixirs6. Elixirs7. Tinctures7. Tinctures8. Proper Administration and Use of Li8. Proper Administration and Use of Li

quid Peroral Dosage Formsquid Peroral Dosage Forms9. Topical Solutions and Tinctures9. Topical Solutions and Tinctures10. Vaginal and Rectal Solutions10. Vaginal and Rectal Solutions11. Topical Tinctures11. Topical Tinctures

12. Topical Oral (Dental) Solutions12. Topical Oral (Dental) Solutions13. Miscellaneous Solutions13. Miscellaneous Solutions14. Nonaqueous Solutions14. Nonaqueous Solutions15. Extraction Methods for Preparing 15. Extraction Methods for Preparing

SolutionsSolutions

In pharmaceutical terms, solutions arIn pharmaceutical terms, solutions are “liquid preparations that contain oe “liquid preparations that contain one or more chemical substances dissone or more chemical substances dissolved in a suitable solvent or mixture olved in a suitable solvent or mixture of mutually miscible solvents”.f mutually miscible solvents”.

Because of a particular pharmaceuticBecause of a particular pharmaceutical solution’s use, it may be classified al solution’s use, it may be classified as as

- oral solution,oral solution,- otic solution,otic solution,- ophthalmic solution,ophthalmic solution,- topical solution. topical solution.

Solutions, because of their compositiSolutions, because of their composition or use, may be classified as other on or use, may be classified as other pharmaceutical dosage forms.pharmaceutical dosage forms.

SyrupsSyrups ElixirsElixirs SpiritsSpirits TincturesTinctures

Certain solutions prepared to be sterCertain solutions prepared to be sterile and pyrogen-free and intended foile and pyrogen-free and intended for parenteral administration are classr parenteral administration are classified asified as injectionsinjections..

Oral solutions, syrups, elixirs, Oral solutions, syrups, elixirs, spirits, and tinctures are spirits, and tinctures are prepared and used for the prepared and used for the specific effects of the medicinal specific effects of the medicinal agents they carry. agents they carry.

In these preparations, the In these preparations, the medicinal agents are intended to medicinal agents are intended to provide systemic effects.provide systemic effects.

1. Solubility1. Solubility

When molecules interact, attractive When molecules interact, attractive and repulsive forces are in effect. and repulsive forces are in effect.

When the attractive and repulsive When the attractive and repulsive forces are equal, the potential forces are equal, the potential energy between two molecules is energy between two molecules is minimum and the system is most minimum and the system is most stable.stable.

When a solute dissolves, the When a solute dissolves, the substance’s intermolecular forces substance’s intermolecular forces of attraction must be overcome of attraction must be overcome by forces of attraction between by forces of attraction between the solute and solvent molecules.the solute and solvent molecules.

This entails breaking the solute-This entails breaking the solute-solute forces and the solvent-solute forces and the solvent-solvent forces to achieve the solvent forces to achieve the solute-solvent attraction.solute-solvent attraction.

The solubility of an agent in a The solubility of an agent in a particular solvent indicates the particular solvent indicates the maximum concentration to which maximum concentration to which a solution may be prepared with a solution may be prepared with that agent and that solvent. that agent and that solvent.

When a solvent at a given When a solvent at a given temperature has dissolved all of temperature has dissolved all of the solute it can, it is said to be the solute it can, it is said to be saturated.saturated.

Through selection of Through selection of a different solubilizing agent or a different solubilizing agent or a different chemical salt form of the a different chemical salt form of the

medicinal agent, medicinal agent, alteration of the pH of a solution, alteration of the pH of a solution, or substitution in part or in whole of or substitution in part or in whole of

the solvent, the solvent, a pharmacist can in certain instances a pharmacist can in certain instances dissolve greater quantities of a solute dissolve greater quantities of a solute than would otherwise be possible.than would otherwise be possible.

Temperature is an important factor Temperature is an important factor in determining the solubility of a in determining the solubility of a drug and in preparing its solution. drug and in preparing its solution.

Most chemicals absorb heat when Most chemicals absorb heat when they are dissolved and are said to they are dissolved and are said to have a positive heat of solution, have a positive heat of solution, resulting in increased solubility resulting in increased solubility with a rise in temperature. with a rise in temperature.

A few chemicals have a negative A few chemicals have a negative heat of solution and exhibit a heat of solution and exhibit a decrease in solubility with a rise in decrease in solubility with a rise in temperature.temperature.

Other factors including Other factors including the various chemical and other the various chemical and other

physical properties of both the physical properties of both the solute and the solvent, pressure, solute and the solvent, pressure,

the pH of the solution, the pH of the solution, the state of subdivision of the the state of subdivision of the

solute, solute, and the physical agitation applied and the physical agitation applied

to the solution as it dissolves to the solution as it dissolves affect solubility.affect solubility.

The solubility of a substance in a The solubility of a substance in a given solvent may be determined given solvent may be determined

by preparing a saturated solution by preparing a saturated solution of it at a specific temperature, of it at a specific temperature,

and determining by chemical and determining by chemical analysis the amount of chemical analysis the amount of chemical dissolved in a given weight of dissolved in a given weight of solution.solution.

The solubility may be expressed as The solubility may be expressed as grams of solute dissolving in grams of solute dissolving in milliliters of solvent. milliliters of solvent.

When the exact solubility has not When the exact solubility has not been determined, general expressions been determined, general expressions of relative solubility may be used. of relative solubility may be used.

These terms are defined in the USP These terms are defined in the USP and presented in Table 12.1and presented in Table 12.1

A great many of the important organic meA great many of the important organic medicinal agents are either weak acids or wedicinal agents are either weak acids or weak bases, and their solubility depends to a ak bases, and their solubility depends to a large measure on the pH of the solvent. large measure on the pH of the solvent.

These drugs react either with strong acids These drugs react either with strong acids or strong bases to form water-soluble salts.or strong bases to form water-soluble salts.

Table 12.2 presents the comparative solubTable 12.2 presents the comparative solubilities of some typical examples of weak acilities of some typical examples of weak acids and weak bases and their salts. ids and weak bases and their salts.

Commonly, salts of organic Commonly, salts of organic compounds are more soluble in compounds are more soluble in water than are the corresponding water than are the corresponding organic bases. organic bases.

Conversely, the organic bases are Conversely, the organic bases are more soluble in organic solvents more soluble in organic solvents than the corresponding salt than the corresponding salt forms.forms.

In most instances, especially for solutiIn most instances, especially for solutions to be taken orally, used ophthalmions to be taken orally, used ophthalmically, or injected, cally, or injected, waterwater is the preferr is the preferred solvent.ed solvent.

When water is used as the primary solWhen water is used as the primary solvent, commonly an auxiliary solvent ivent, commonly an auxiliary solvent is also employed to augment the solves also employed to augment the solvent action of water or to contribute to a nt action of water or to contribute to a product’s chemical or physical stabilproduct’s chemical or physical stability. ity.

Alcohol, glycerin,Alcohol, glycerin, and and propylene glycol,propylene glycol, have been quite effective in have been quite effective in contributing to the desired contributing to the desired characteristics of pharmaceutical characteristics of pharmaceutical solutions and in maintaining their solutions and in maintaining their stability.stability.

A number of fixed oils, such as A number of fixed oils, such as corn oilcorn oil, , cottonseed oilcottonseed oil, , peanut oilpeanut oil, and , and sesame sesame oiloil, are useful solvents, particularly in , are useful solvents, particularly in the preparation of the preparation of oleaginous oleaginous injectionsinjections, and are recognized in the , and are recognized in the official compendia for this purpose.official compendia for this purpose.

2. Some Solvents for Liquid Preparations2. Some Solvents for Liquid Preparations

(1) Alcohol, USP: Ethyl Alcohol, (1) Alcohol, USP: Ethyl Alcohol, Ethanol Ethanol

(2) Diluted Alcohol, NF(2) Diluted Alcohol, NF

(3) Alcohol, Rubbing(3) Alcohol, Rubbing

(4) Glycerin, USP (Glycerol)(4) Glycerin, USP (Glycerol)

(5) Isopropyl Rubbing Alcohol(5) Isopropyl Rubbing Alcohol

(6) Propylene Glycol, USP(6) Propylene Glycol, USP

(7) Purified Water, USP(7) Purified Water, USP

(1) Alcohol, USP: Ethyl Alcohol, Ethanol(1) Alcohol, USP: Ethyl Alcohol, Ethanol

Alcohol is the most useful solvent in pharAlcohol is the most useful solvent in pharmacy next to water. USP, is 94.9 to 96% Cmacy next to water. USP, is 94.9 to 96% C22

HH55OH by volume (i.e., v/v)OH by volume (i.e., v/v)

Together with water it forms a hydroalcohTogether with water it forms a hydroalcoholic mixture that dissolves both alcohol-soolic mixture that dissolves both alcohol-soluble and water-soluble substances, a featluble and water-soluble substances, a feature especially useful in the extraction of aure especially useful in the extraction of active constituents from crude drugs.ctive constituents from crude drugs.

Alcohol has been well recognized as a sAlcohol has been well recognized as a solvent and excipient in the formulation olvent and excipient in the formulation of oral pharmaceutical products.of oral pharmaceutical products.

Certain drugs are insoluble in water anCertain drugs are insoluble in water and must be dissolved in an alternative ved must be dissolved in an alternative vehicle.hicle.

Alcohol is frequently used with other sAlcohol is frequently used with other s

olvents, such as glycols and glycerin, to olvents, such as glycols and glycerin, to reduce the amount of alcohol required.reduce the amount of alcohol required.

It also is used in liquid products as aIt also is used in liquid products as an antimicrobial preservative alone or n antimicrobial preservative alone or with parabens, benzoates, sorbates, with parabens, benzoates, sorbates, and other agents.and other agents.

However, concern has been expresseHowever, concern has been expressed over the undesired pharmacologic d over the undesired pharmacologic and potential toxic effects of alcohol. and potential toxic effects of alcohol.

Children under 6 years of age alcohol limit 0.5%6-12 years of age 5%Over 12 years of age and adults 10%

OTC

(2) Diluted Alcohol, NF(2) Diluted Alcohol, NF

Diluted Alcohol, NF, is prepared by Diluted Alcohol, NF, is prepared by mixing equal volumes of Alcohol, USmixing equal volumes of Alcohol, USP, and Purified Water, USP.P, and Purified Water, USP.

The strength of Diluted Alcohol, NF, The strength of Diluted Alcohol, NF, is not exactly half that of the more cois not exactly half that of the more concentrated alcohol but slightly greatncentrated alcohol but slightly greater, approximately 49%.er, approximately 49%.

Diluted alcohol is a useful hydroalcoDiluted alcohol is a useful hydroalcoholic solvent in various pharmaceutiholic solvent in various pharmaceutical processes and preparations. cal processes and preparations.

(3) Alcohol, Rubbing(3) Alcohol, Rubbing

Rubbing alcohol contains about 70% Rubbing alcohol contains about 70% ethyl alcohol by volume, the remainder ethyl alcohol by volume, the remainder consisting of water, denaturants with consisting of water, denaturants with or without color additives and perfume or without color additives and perfume oils, and stabilizers.oils, and stabilizers.

Sucrose octaacetate ( 蔗糖八乙酸酯） 355 mg

or (denatonium benzoate 地那铵苯甲酸盐 1.4 mg)

100 ml

8 parts acetone1.5 parts methyl isobutyl ketone

100 parts ethyl alcohol

denaturants

It is employed as a rubefacient exterIt is employed as a rubefacient externally and as a soothing rub for bedrinally and as a soothing rub for bedridden patients, a germicide for instrudden patients, a germicide for instruments, and a skin cleanser prior to inments, and a skin cleanser prior to injection.jection.

It also used as a vehicle for topical prIt also used as a vehicle for topical preparations.eparations.

The product is volatile and flammablThe product is volatile and flammable and should be stored in tight contaie and should be stored in tight containers remote from fire.ners remote from fire.

(4) Glycerin, USP (Glycerol)(4) Glycerin, USP (Glycerol)

Glycerin is a clear syrupy liquid with a Glycerin is a clear syrupy liquid with a sweet taste. It is miscible with both sweet taste. It is miscible with both water and alcohol. water and alcohol.

Glycerin has preservative qualities Glycerin has preservative qualities and is often used as a stabilizer and and is often used as a stabilizer and as an auxiliary solvent in conjunction as an auxiliary solvent in conjunction with water or alcohol. with water or alcohol.

It is used in many internal It is used in many internal preparations.preparations.

(5) Isopropyl Rubbing Alcohol(5) Isopropyl Rubbing Alcohol

Isopropyl rubbing alcohIsopropyl rubbing alcohol is about 70% by volumol is about 70% by volume isopropyl alcohol, the re isopropyl alcohol, the remainder consisting of wemainder consisting of water with or without coloater with or without color additives, stabilizers, ar additives, stabilizers, and perfume oils.nd perfume oils.

It is used externally as a rIt is used externally as a rubefacient and soothing ubefacient and soothing rub and as a vehicle for trub and as a vehicle for topical products.opical products.

Commercially 91% isopropyl alcohol

solutionfor diabetic patientsdisinfecting needles,

syringes and skin

(6) Propylene Glycol, USP(6) Propylene Glycol, USP

Propylene glycol, a viscous liquid, Propylene glycol, a viscous liquid, is miscible with water and alcohol.is miscible with water and alcohol.

It is a useful solvent with a wide It is a useful solvent with a wide range of applications and is range of applications and is frequently substituted for glycerin frequently substituted for glycerin in modern pharmaceutical in modern pharmaceutical formulations.formulations.

(7) Purified Water, USP(7) Purified Water, USP

Purified Water, USP, is obtained Purified Water, USP, is obtained by by distillationdistillation, , ion exchange ion exchange treatmenttreatment, , reverse osmosisreverse osmosis, or , or other suitable processother suitable process. .

It is prepared from water It is prepared from water complying with the federal complying with the federal Environmental Protection Agency Environmental Protection Agency with respect to drinking water. with respect to drinking water.

Compared with ordinary drinking water, Compared with ordinary drinking water, Purified WaterPurified Water, USP is more free of soli, USP is more free of soli

d impurities. d impurities. When evaporated to dryness, it must nWhen evaporated to dryness, it must n

ot yield greater than 0.001% of residue ot yield greater than 0.001% of residue (1 mg of total solids per 100 mL of samp(1 mg of total solids per 100 mL of sample evaporated). le evaporated).

Purified Water, USP is intended for use Purified Water, USP is intended for use in the preparation of in the preparation of aqueous dosage foaqueous dosage formsrms, except those intended for parente, except those intended for parenteral administration (injetions).ral administration (injetions).

Distillation MethodDistillation Method

The first portion of aqueous The first portion of aqueous distillate (about the first 10 to 20%) distillate (about the first 10 to 20%) must be discarded.must be discarded.

The last portion of water (about The last portion of water (about 10% of the original volume of water 10% of the original volume of water ) remaining in the distillation ) remaining in the distillation apparatus must be discarded and apparatus must be discarded and not subjected to further distillation.not subjected to further distillation.

Ion-exchange methodIon-exchange method

On a large or small scale, the ion-On a large or small scale, the ion-exchange method for the preparation exchange method for the preparation of purified water offers a number of of purified water offers a number of advantages over the distillation advantages over the distillation method.method.

The ion-exchange process permits The ion-exchange process permits ease of operation, minimal ease of operation, minimal maintenance, and a more mobile maintenance, and a more mobile facility.facility.

There are mainly two types of resins iThere are mainly two types of resins in column ion-exchangen column ion-exchange

- the cationthe cation, or , or acid exchangersacid exchangers, which , which permit the exchange of the cations in permit the exchange of the cations in solution with hydrogen ion from the rsolution with hydrogen ion from the resinesin

- the anionthe anion, or , or base exchange resinsbase exchange resins, w, which permit the removal of anions.hich permit the removal of anions.

- These two processes are successively These two processes are successively or simultaneously employed to removor simultaneously employed to remove both cations and anions from water.e both cations and anions from water.

Cation exchangeCation exchange H-Resin + MH-Resin + M++ + X + X- - + H+ H22OO M-Resin + M-Resin +

HH++ + X + X- - + H+ H22O (pure)O (pure)

Anion exchangeAnion exchange Resin-NHResin-NH22 + H + H++ + X + X- - + H+ H22OO Resin-NH Resin-NH22HX + HHX + H22O (pure)O (pure)

Water purified in this manner is referreWater purified in this manner is referred to asd to as demineralized demineralized or or de-ionized watde-ionized waterer..

Reverse osmosisReverse osmosis In this process, a pressurized stream of wIn this process, a pressurized stream of w

ater is passed parallel to the inner side of ater is passed parallel to the inner side of a filter membrane core.a filter membrane core.

A portion of the feed water permeates thA portion of the feed water permeates the membrane as filtrate.e membrane as filtrate.

The water that has passed through the syThe water that has passed through the system is referred to as the concentrate.stem is referred to as the concentrate.

The flow in this crossflow system is from The flow in this crossflow system is from a more concentrated to a less concentrata more concentrated to a less concentrated solution-thus the term reverse osmosied solution-thus the term reverse osmosis.s.

Cross-flow filter membranes can removCross-flow filter membranes can remove particles defined in the range of e particles defined in the range of

microfiltrationmicrofiltration (0.1 to 2 microns, e.g., b (0.1 to 2 microns, e.g., bacteria)acteria)

ultrafiltrationultrafiltration (0.01 to 0.1 microns, e.g., (0.01 to 0.1 microns, e.g., virus)virus)

nanofiltrationnanofiltration (0.001 to 0.01 microns, e. (0.001 to 0.01 microns, e.g., organic compounds in the molecular g., organic compounds in the molecular weight range of 300 to 1000)weight range of 300 to 1000)

reverse osmosisreverse osmosis (particles smaller than (particles smaller than 0.001 microns)0.001 microns)

Reverse osmosisReverse osmosis removes virtually all removes virtually all virusvirus bacteriabacteria pyrogenspyrogens organic moleculesorganic molecules and 90and 9099% of all ions.99% of all ions.

3. Preparation of Solutions3. Preparation of Solutions

Most pharmaceutical solutions are Most pharmaceutical solutions are unsaturated with solute. Thus the unsaturated with solute. Thus the amounts of solute to be dissolved amounts of solute to be dissolved are usually well below the capacity are usually well below the capacity of the volume of solvent employed. of the volume of solvent employed.

The strengths of pharmaceutical The strengths of pharmaceutical preparations are usually expressed preparations are usually expressed in terms of percent strength, in terms of percent strength, expressions of ratio strength may expressions of ratio strength may be used. These expressions and be used. These expressions and examples are shown in Table 12.4.examples are shown in Table 12.4.

The symbol % used without qualification The symbol % used without qualification (as with w/v, v/v, or w/w) means (as with w/v, v/v, or w/w) means

percent weight in volume for solutions or spercent weight in volume for solutions or suspensions of solids in liquids; uspensions of solids in liquids;

percent weight in volume for solutions of gpercent weight in volume for solutions of gases in liquids; ases in liquids;

percent volume in volume for solutions of lpercent volume in volume for solutions of liquids in liquids; iquids in liquids;

and weight in weight for mixtures of solids and weight in weight for mixtures of solids and semisolids. and semisolids.

To hasten dissolution, a pharmacist To hasten dissolution, a pharmacist may employ one of several techniquemay employ one of several techniques, such as s, such as

applying heat, applying heat, reducing the particle size of the solutreducing the particle size of the solut

e, e, using a solubilizing agent, using a solubilizing agent, or subjecting the ingredients to vigoror subjecting the ingredients to vigor

ous agitation.ous agitation.

Most chemical agents are more Most chemical agents are more soluble at elevated temperatures soluble at elevated temperatures than at room temperature or below than at room temperature or below because an endothermic reaction because an endothermic reaction between the heat to enhance between the heat to enhance dissolution.dissolution.

In addition to or instead of raising In addition to or instead of raising the temperature of the solvent to the temperature of the solvent to increase the rate of solution, a increase the rate of solution, a pharmacist may choose to decrease pharmacist may choose to decrease the particle size of the solute.the particle size of the solute.

Most solutions are prepared by Most solutions are prepared by

simple mixing of the solutes with simple mixing of the solutes with

the solvent. the solvent.

On an industrial scale, solutions On an industrial scale, solutions

are prepared in large mixing are prepared in large mixing

vessels with ports for mechanical vessels with ports for mechanical

stirrers. stirrers.

4. Oral Solutions and Preparations for 4. Oral Solutions and Preparations for Oral SolutionOral Solution

Most solutions intended for oral admMost solutions intended for oral administration contain flavorants and colinistration contain flavorants and colorants to make the medication more orants to make the medication more attractive and palatable. attractive and palatable.

When needed, they may also contain When needed, they may also contain stabilizers to maintain the chemical stabilizers to maintain the chemical and physical stability of the medicinand physical stability of the medicinal agents and preservatives to prevenal agents and preservatives to prevent the growth of microorganisms in tht the growth of microorganisms in the solution.e solution.

The formulation pharmacist must be The formulation pharmacist must be wary of chemical interactions wary of chemical interactions between the various components of a between the various components of a solution that may alter the solution that may alter the preparation’s stability and/or potency.preparation’s stability and/or potency.

Liquid pharmaceuticals for oral Liquid pharmaceuticals for oral administration are usually formulated administration are usually formulated such that the patient receives the such that the patient receives the usual dose of the medication in a usual dose of the medication in a conveniently administered volume, as conveniently administered volume, as 5mL, 10mL, or 15mL. 5mL, 10mL, or 15mL.

(1) Dry Mixtures for Solution(1) Dry Mixtures for Solution

A number of medicinal agents, A number of medicinal agents, particularly certain antibiotics, have particularly certain antibiotics, have insufficient stability in aqueous insufficient stability in aqueous solution to meet extended shelf life solution to meet extended shelf life periods. periods.

Commercial manufacturers of these Commercial manufacturers of these products provide them to the products provide them to the pharmacist in dry powder or granule pharmacist in dry powder or granule form for reconstitution with a form for reconstitution with a prescribed amount of purified water prescribed amount of purified water immediately before dispensing to the immediately before dispensing to the patient.patient.

The dry powder mixture contains all The dry powder mixture contains all of the formulative components, incluof the formulative components, including ding drug, flavorant, colorant, bufferdrug, flavorant, colorant, buffers, and otherss, and others, except for the solvent., except for the solvent.

Once reconstituted by the pharmacisOnce reconstituted by the pharmacist, the solution remains stable when st, the solution remains stable when stored in the refrigerator for the labeltored in the refrigerator for the labeled period, usually ed period, usually 7 to 14 days7 to 14 days, depen, depending on the preparation.ding on the preparation.

(2) Oral Solutions(2) Oral Solutions

The pharmacist shoule be sufficiently The pharmacist shoule be sufficiently knowledgeable about the dispensed prknowledgeable about the dispensed product to expertly advise the patient of toduct to expertly advise the patient of the he proper use, dosage, method of admiproper use, dosage, method of administration and storage of the product.nistration and storage of the product.

Table 12.5 presents examples of some Table 12.5 presents examples of some oral solutions.oral solutions.

Knowledge of Knowledge of the the solubility solubility and and stabilitystability

characteristics of the medicinal characteristics of the medicinal agents agents

and the and the solventssolvents employed in the employed in the commercial products commercial products

is useful to the pharmacist for is useful to the pharmacist for informing the patient of the informing the patient of the advisability of mixing the solution advisability of mixing the solution with with juice, milk, or other beveragejuice, milk, or other beverage upon administration.upon administration.

(3) Oral Rehydration Solutions(3) Oral Rehydration Solutions

Rapid fluid loss associated with Rapid fluid loss associated with diarrhea can lead to dehydration and diarrhea can lead to dehydration and ultimately death in some patients, ultimately death in some patients, particularly infants.particularly infants.

Diarrhea is characterized by an Diarrhea is characterized by an increased frequency of loose, watery increased frequency of loose, watery stools, and because of the rapid fluid stools, and because of the rapid fluid loss, dehydration can be an outcome.loss, dehydration can be an outcome.

During diarrhea, the small intestine secrDuring diarrhea, the small intestine secretes far more than the normal amount of etes far more than the normal amount of fluid and electrolytes, and this simply exfluid and electrolytes, and this simply exceeds the ability of the large intestine to ceeds the ability of the large intestine to reabsorb it. reabsorb it.

This fluid loss, which occurs mostly froThis fluid loss, which occurs mostly from the body’s extracellular fluid comparm the body’s extracellular fluid compartment, can lead to a progressive loss of bltment, can lead to a progressive loss of blood volume culminating in hypovolemic ood volume culminating in hypovolemic shock.shock.

Oral rehydration solutions are usually effOral rehydration solutions are usually effective in treatment of patients with mild ective in treatment of patients with mild volume depletion, 5 to 10% of body weighvolume depletion, 5 to 10% of body weight. t.

A liter or typical oral rehydration solutioA liter or typical oral rehydration solutio

n contains 45 mEq Nan contains 45 mEq Na++, 20 mEq K, 20 mEq K++, 35 mE, 35 mEq Clq Cl--, 30 mEq citrate, and 25 g dextrose. , 30 mEq citrate, and 25 g dextrose.

It is important that the user add the speciIt is important that the user add the specific amount of water needed to prepare thfic amount of water needed to prepare the powder forms. e powder forms.

(4) Magnesium Citrate Oral Solution(4) Magnesium Citrate Oral Solution

Magnesium citrate oral solution is a Magnesium citrate oral solution is a colorless to slightly yellow, clear, effcolorless to slightly yellow, clear, effervescent liquid having a sweet, acidervescent liquid having a sweet, acidulous taste and a lemon flavor. ulous taste and a lemon flavor.

The solution is employed as a saline The solution is employed as a saline cathartic with the citric acid, lemon cathartic with the citric acid, lemon oil, syrup, carbonation.oil, syrup, carbonation.

The solution is prepared by The solution is prepared by reacting official magnesium reacting official magnesium

carbonate with an excess of citric carbonate with an excess of citric acid, acid,

flavoring and sweetening the flavoring and sweetening the solution with lemon oil and syrup, solution with lemon oil and syrup,

filtering with talc, filtering with talc, and then carbonating it by the and then carbonating it by the

addition of either potassium or addition of either potassium or sodium bicarbonate.sodium bicarbonate.

(5) Oral Colonic Lavage Solution(5) Oral Colonic Lavage Solution

Polyethylene glycol 3350 236.00 g Sodium sulfate 22.74 gSodium bicarbonate 6.74 gSodium chloride 5.86 gPotassium chloride 2.97 g

In 4800 ml disposable container

The PEG acts as an osmotic agent within the gastrointestinal tract and the balanced electrolyte concentration results in virtually no net absorption or secretion of ions.

(6) Sodium Citrate and Citric Acid Oral (6) Sodium Citrate and Citric Acid Oral SolutionSolution

The solution is administered orally The solution is administered orally in doses of 10 to 30 ml/4 times.in doses of 10 to 30 ml/4 times.

1 ml aqueous solution100 mg sodium citrate

67 mg citric acid

Uric acidCystine calculi

Systemic alkalinization

5. Syrups5. Syrups Syrups are concentrated aqueous preSyrups are concentrated aqueous pre

parations of a sugar or sugar substituparations of a sugar or sugar substitute with or without flavoring agents ate with or without flavoring agents and medicinal substances.nd medicinal substances.

Syrups containing flavoring agents bSyrups containing flavoring agents but not medicinal substances are calleut not medicinal substances are called nonmedicated or flavored vehicles d nonmedicated or flavored vehicles (syrups).(syrups).

sucrosesucrosepurified waterpurified water

flavoring agentsflavoring agentscoloring agentscoloring agents

therapeutic agenttherapeutic agent

Medicated Medicated syrupssyrups

Syrups provided a pleasant means Syrups provided a pleasant means of administering a liquid form of a of administering a liquid form of a disagreeable-tasting drugdisagreeable-tasting drug..

They are particularly effective in They are particularly effective in the administration of drugs to the administration of drugs to youngstersyoungsters, since their pleasant , since their pleasant taste usually dissipates any taste usually dissipates any reluctance on the part of the child reluctance on the part of the child to take the medicine. to take the medicine.

Any water-soluble drug that is stable Any water-soluble drug that is stable in aqueous solution may be added to in aqueous solution may be added to a flavored syrup. a flavored syrup.

However, care must be exercised to eHowever, care must be exercised to ensure compatibility between the drunsure compatibility between the drug substance and the other formulativg substance and the other formulative components of the syrup. e components of the syrup.

(1) Components of Syrups(1) Components of Syrups

Most syrups contain the following coMost syrups contain the following components in addition to the purified mponents in addition to the purified water and any medicinal agents preswater and any medicinal agents present:ent:

SugarAntimicrobial Pres

ervativesFlavorantColorants

Sucrose and non-sucrose Sucrose and non-sucrose based syrupbased syrup

SucroseDextrose

SucroseDextrose

MethylcelluloseHydroxyethylcellulose

MethylcelluloseHydroxyethylcellulose

Non-sugarsSorbitolGlycerinPropylene glycol

Non-sugarsSorbitolGlycerinPropylene glycol

Most syrups contain a high Most syrups contain a high proportion of sucrose, usually 60-proportion of sucrose, usually 60-80%.80%.

Concentrated sugar solutions are Concentrated sugar solutions are quite resistant to microbial growth.quite resistant to microbial growth.

Simple syrup85 g sucrose

+purified water=100 ml syrup

Antimicrobial preservativeAntimicrobial preservative

Benzoic acid (0.1 to 0.2%)Sodium benzoate (0.1 to 0.2%)

Methyl-, propyl-, and butylparabens (0.1%)Alcohol (15 to 20%)

Syrups can be preserved bySyrups can be preserved by

1)1) storage at low temperaturestorage at low temperature

2)2) adding preservatives in the adding preservatives in the formulationformulation

3)3) by the maintenance of a high by the maintenance of a high concentration of sucrose as a concentration of sucrose as a part of the formulationpart of the formulation

Example Example

RxRxActive drugActive drug 5ml volume occupied5ml volume occupiedOther drug solidsOther drug solids 3 ml volume occupied3 ml volume occupiedGlycerinGlycerin 15 ml15 mlSucroseSucrose 25 g25 gEthanolEthanol 95% q.s.95% q.s.Purified water Purified water q.s.q.s. 100 ml100 ml

How much alcohol would be required to pHow much alcohol would be required to preserve this prescription?reserve this prescription?

FlavorantFlavorant

Because syrups are aqueous preparations, Because syrups are aqueous preparations, these flavorants must be water soluble.these flavorants must be water soluble.

Synthetic flavorantsNaturally occurring materials

Volatile oilsVanillin

ColorantColorant

The colorant is generally The colorant is generally water soluble, water soluble, nonreactive with the other syrup cononreactive with the other syrup co

mponents, mponents, color stable at the pH range and undcolor stable at the pH range and und

er the intensity of light that the syrup er the intensity of light that the syrup is likely to encounter during its shelf is likely to encounter during its shelf life.life.

green with mintbrown with chocolate

(2) Preparation of Syrups(2) Preparation of Syrups

Syrups are frequently prepared by onSyrups are frequently prepared by one of four general methods.e of four general methods.

1)1) solution of the ingredients with the aid of solution of the ingredients with the aid of heat,heat,

2)2) solution of the ingredients by agitation witsolution of the ingredients by agitation without the use of heat, or the simple admixtuhout the use of heat, or the simple admixture of liquid components,re of liquid components,

3)3) addition of sucrose to a prepared medicateaddition of sucrose to a prepared medicated liquid or to a flavored liquid, d liquid or to a flavored liquid,

4)4) percolation of either the source of the medpercolation of either the source of the medicating substance or of the sucrose.icating substance or of the sucrose.

ⅠⅠ. Solution With the Aid of . Solution With the Aid of HeatHeat

Syrups are prepared by this Syrups are prepared by this method method

when it is desired to prepare the when it is desired to prepare the syrup as quickly as possible,syrup as quickly as possible,

when the syrup’s components when the syrup’s components are not damaged or volatilized are not damaged or volatilized by heat. by heat.

In this method the sugar is generallIn this method the sugar is generally added to the purified water, and hy added to the purified water, and heat is applied until the sugar is disseat is applied until the sugar is dissolved.olved.

then other heat-stable components then other heat-stable components are added to the hot syrup, are added to the hot syrup,

the mixture is allowed to cool, the mixture is allowed to cool, its volume is adjusted to the proper its volume is adjusted to the proper

level by addition of purified water.level by addition of purified water.

If heatlabile agents or volatile substaIf heatlabile agents or volatile substances, such as volatile flavoring oils ances, such as volatile flavoring oils and alcohol, are to be added, nd alcohol, are to be added,

they are generally added to the syrup they are generally added to the syrup after the sugar is dissolved by heat, after the sugar is dissolved by heat,

and the solution is rapidly cooled to rand the solution is rapidly cooled to room temperature. oom temperature.

Because of the prospect of Because of the prospect of decomposition by heat, syrups decomposition by heat, syrups cannot be sterilized by autoclaving.cannot be sterilized by autoclaving.

The use of The use of boiled purified waterboiled purified water in in the preparation of a syrup can the preparation of a syrup can enhance its permanency, and enhance its permanency, and the the addition of preservative agentsaddition of preservative agents, , when permitted, can protect it when permitted, can protect it during its shelf life. during its shelf life.

Storage in Storage in a tight containera tight container is a is a requirement for all syrups.requirement for all syrups.

ⅡⅡ. Solution by Agitation Without t. Solution by Agitation Without the Aid of Heathe Aid of Heat

To avoid heat-induced inversion of sTo avoid heat-induced inversion of sucrose, a syrup may be prepared witucrose, a syrup may be prepared without heat by agitation.hout heat by agitation.

On a small scale, sucrose and other fOn a small scale, sucrose and other formulative agents may be dissolved iormulative agents may be dissolved in purified water and thorough agitatn purified water and thorough agitated of the mixture.ed of the mixture.

This process is more time consuming than This process is more time consuming than use of heat, but the product has maximum use of heat, but the product has maximum stability.stability.

Huge glass-lined or stainless steel tanks with Huge glass-lined or stainless steel tanks with mechanical stirrers or agitators are mechanical stirrers or agitators are employed in large-scale preparation of employed in large-scale preparation of syrups.syrups.

When solid agents are to be added to a syrup, When solid agents are to be added to a syrup, it is best to dissolve them in a minimal it is best to dissolve them in a minimal amount of purified water and incorporate the amount of purified water and incorporate the resulting solution into the syrup.resulting solution into the syrup.

ⅢⅢ . Addition of Sucrose to a Medic. Addition of Sucrose to a Medicated Liquid or to a Flavored Liquidated Liquid or to a Flavored Liquid

Occasionally a medicated liquid, sucOccasionally a medicated liquid, such as a tincture or fluidextract, is emph as a tincture or fluidextract, is employed as the source of medication in tloyed as the source of medication in the preparation of a syrup.he preparation of a syrup.

Many such tinctures and fluidextractMany such tinctures and fluidextracts contain alcohol-soluble constituents contain alcohol-soluble constituents and are prepared with alcoholic or s and are prepared with alcoholic or hydroalcoholic vehicles. hydroalcoholic vehicles.

If the alcohol-soluble components arIf the alcohol-soluble components are desired medicinal agents, some mee desired medicinal agents, some means of rendering them water soluble ans of rendering them water soluble is employed.is employed.

If the tincture or fluidextract is misciIf the tincture or fluidextract is miscible with aqueous preparations, it mable with aqueous preparations, it may be added derectly to simple syrup oy be added derectly to simple syrup or to a flavored syrup.r to a flavored syrup.

ⅣⅣ . Percolation. Percolation （渗漉）（渗漉） In the percolation method, either In the percolation method, either

sucrose may be percolated to prepare sucrose may be percolated to prepare the syrup, or the source of the the syrup, or the source of the medicinal component may be medicinal component may be percolated to form an extractive to percolated to form an extractive to which sucrose or syrup may be added.which sucrose or syrup may be added.

This latter method really is two This latter method really is two separate procedures: first the separate procedures: first the preparation of the extractive of the preparation of the extractive of the drug and then the preparation of the drug and then the preparation of the syrup. syrup.

Ipecac syrup

GlycerinSyrup

Extractiveof powdered ipecac

Percolation

Ipecacdried rhizome

roots of cephaelis ipecacuanha

alkaloidsemetinecephaelinepsychotrine

alkaloidsemetinecephaelinepsychotrine

The usual dose of ipecac syrup is 15 The usual dose of ipecac syrup is 15 ml.ml.

This amount of syrup is commonly uThis amount of syrup is commonly used in the management of poisoning sed in the management of poisoning in children when the evacuation of tin children when the evacuation of the stomach contents is desirable.he stomach contents is desirable.

Ipecac syrup also has some applicatiIpecac syrup also has some application as a nauseant expectorant, in doson as a nauseant expectorant, in doses smaller than the emetic dose.es smaller than the emetic dose.

6. Elixirs6. Elixirs

Elixirs are clear, sweetened hydroalcElixirs are clear, sweetened hydroalcoholic solutions intended for oral usoholic solutions intended for oral use and are uaually flavored to enhance and are uaually flavored to enhance their palatability.e their palatability.

Nonmedicated elixirs are employed aNonmedicated elixirs are employed as vehicles;s vehicles;

Medicated elixirs are used for the theMedicated elixirs are used for the therapeutic effect of the medicinal substrapeutic effect of the medicinal substances they contain.ances they contain.

Compared with syrups, elixirs are Compared with syrups, elixirs are usually less sweet and less viscous.usually less sweet and less viscous.

Elixirs are better able than aqueous Elixirs are better able than aqueous

syrups to maintain both water-syrups to maintain both water-soluble and alcohol-soluble soluble and alcohol-soluble components in solution.components in solution.

Each elixir requires a specific blend Each elixir requires a specific blend of alcohol and water to maintain all of alcohol and water to maintain all of the components in solution.of the components in solution.

In addition to alcohol and water, othIn addition to alcohol and water, other solvents, such as er solvents, such as glycerin glycerin and and propropylene glycolpylene glycol, are frequently emplo, are frequently employed in elixirs as adjunctive solvents.yed in elixirs as adjunctive solvents.

Although many elixirs are sweeteneAlthough many elixirs are sweetened with sucrose or with a sucrose syrd with sucrose or with a sucrose syrup, some use up, some use sorbitol, glycerin, and/sorbitol, glycerin, and/or artificial sweeteners. or artificial sweeteners.

All elixirs contain All elixirs contain flavorings flavorings to to increase their palatability, and increase their palatability, and most elixirs have most elixirs have coloring agentscoloring agents to enhance their appearance.to enhance their appearance.

Elixirs containing more than Elixirs containing more than 10 10 to 12% of alcoholto 12% of alcohol are usually are usually self-preserving and do not self-preserving and do not require the addition of an require the addition of an antimicrobial agent. antimicrobial agent.

One One advantageadvantage of elixirs over their of elixirs over their counterpart drugs in solid dosage counterpart drugs in solid dosage forms is the forms is the flexibility and ease of flexibility and ease of dosage administration to patientsdosage administration to patients who have difficulty swallowing solid who have difficulty swallowing solid forms.forms.

A A disadvantage disadvantage of elixirs for children of elixirs for children and for adults who choose to avoid and for adults who choose to avoid alcohol is their alcoholic content.alcohol is their alcoholic content.

Elixirs should be stored in Elixirs should be stored in tight, tight, light-resistant containers and light-resistant containers and protected from excessive heat.protected from excessive heat.

(1) Preparation of Elixirs(1) Preparation of Elixirs

Elixirs are usually prepared by Elixirs are usually prepared by simple solution with agitation simple solution with agitation and/or by admixture of two or more and/or by admixture of two or more liquid ingredients.liquid ingredients.

Alcohol-soluble and water-soluble Alcohol-soluble and water-soluble components are generally dissolved components are generally dissolved separately in alcohol and in purified separately in alcohol and in purified water, respectively.water, respectively.

Then the aqueous solution is added Then the aqueous solution is added to the alcoholic solution to maintain to the alcoholic solution to maintain the highest possible alcoholic the highest possible alcoholic strength at all times so that minimal strength at all times so that minimal separation of the alcohol-soluble separation of the alcohol-soluble components occurs.components occurs.

When the two solutions are When the two solutions are completely mixed, the mixture is completely mixed, the mixture is made to volume with the specified made to volume with the specified solvent or vehicle.solvent or vehicle.

Frequently the final mixture will Frequently the final mixture will be cloudy because of separation be cloudy because of separation of some of the flavoring oils by of some of the flavoring oils by the reduced alcoholic the reduced alcoholic concentration.concentration.

TalcFilter

(2) Nonmedicated Elixirs(2) Nonmedicated Elixirs

Nonmedicated elixirs may be useful Nonmedicated elixirs may be useful to the pharmacist in the extemporato the pharmacist in the extemporaneous filling of prescriptions involvneous filling of prescriptions involving ing

(a)(a) the addition of a therapeutic agent tthe addition of a therapeutic agent to a pleasant-tasting vehicle,o a pleasant-tasting vehicle,

(b)(b) dilution of an existing medicated elidilution of an existing medicated elixir.xir.

In selecting a liquid vehicle for a druIn selecting a liquid vehicle for a drug substance, the pharmacist should bg substance, the pharmacist should be concerned with the solubility and se concerned with the solubility and stability of the drug substance in watetability of the drug substance in water and alcohol.r and alcohol.

All components should be chemicallAll components should be chemically and physically compatible.y and physically compatible.

The three most commonly used nonThe three most commonly used nonmedicated elixirs were medicated elixirs were

aromatic elixir, aromatic elixir, compound benzaldehyde elixir compound benzaldehyde elixir （复（复方安息香醛酏剂）方安息香醛酏剂） , ,

isoalcoholic elixir. isoalcoholic elixir.

(3) Medicated Elixirs(3) Medicated Elixirs

Antihistamines elixirsAntihistamines elixirs are useful are useful primarily in the symptomatic primarily in the symptomatic relief of certain allergic disorders.relief of certain allergic disorders.

The most common untoward The most common untoward effect is sedation.effect is sedation.

Other common adverse effects Other common adverse effects include dryness of the nose, include dryness of the nose, throat, and mouth; dizziness; and throat, and mouth; dizziness; and disturbed concentration.disturbed concentration.

Barbiturate sedative/hypnotic Barbiturate sedative/hypnotic elixirselixirs

Barbiturates are administered in Barbiturates are administered in small small dosesdoses in the in the daytime daytime hours as sedatives hours as sedatives to reduce restlessness and emotional to reduce restlessness and emotional tension.tension.

Greater doses may be given before Greater doses may be given before bedtime as hypnotics to release bedtime as hypnotics to release insomnia.insomnia.

long-actingintermediate-acting

short-actingultrashort-acting

phenobarbitalamobarbital

pentobarbitolsecobarbitolthiopental

Phenobarbital ElixirPhenobarbital Elixir

Phenobarbital elixir is formulated to conPhenobarbital elixir is formulated to contain phenobarbital 0.4%,which provides tain phenobarbital 0.4%,which provides about 20 mg of drug per teaspoonful (5mabout 20 mg of drug per teaspoonful (5mL)of elixir.L)of elixir.

Orange oilColored red

SyrupGlycerin

Digoxin ElixirDigoxin Elixir

Digoxin is poisonous, and its dose mDigoxin is poisonous, and its dose must be carefully determined and admust be carefully determined and administered to each individual patient.inistered to each individual patient.The official elixir contains about The official elixir contains about 10% of al10% of alcoholcohol..

100 ml elixir4.5 mg to 5.25 mg

0.25 mg/5mL teaspoonful

Cardiotonic agent1.5 mg initial therapy

0.5 mg maintenance therapy

Dropper

Dropper

7. Tinctures7. Tinctures

Tinctures are alcoholic or hydroalcoTinctures are alcoholic or hydroalcoholic solutions prepared from vegetaholic solutions prepared from vegetable materials or from chemical substble materials or from chemical substances.ances.

They vary in method of preparation, They vary in method of preparation, strength of the active ingredient, alcstrength of the active ingredient, alcoholic content, and intended use in oholic content, and intended use in medicine or pharmacy.medicine or pharmacy.

Depending on the praparation, tinctDepending on the praparation, tinctures contain alcohol in amounts ranures contain alcohol in amounts ranging from approximately 15 to 80%. ging from approximately 15 to 80%.

The alcohol content protects against The alcohol content protects against microbial growth and keeps the alcomicrobial growth and keeps the alcohol-soluble extractives in solution.hol-soluble extractives in solution.

In addition to alcohol, other solvents,In addition to alcohol, other solvents, such as glycerin, may be employed. such as glycerin, may be employed.

Tinctures must be Tinctures must be tightly stopperedtightly stoppered and and not exposed to excessive temperatures.not exposed to excessive temperatures.

Many tinctures must be stored in Many tinctures must be stored in light-rlight-resistant containersesistant containers and protected from s and protected from sunlight.unlight.

paregoric camphorated

tincture of opium

8. Proper Administration and Use 8. Proper Administration and Use of Liquid Peroral Dosage Formsof Liquid Peroral Dosage Forms

The liquid dosage forms should be The liquid dosage forms should be measured out in calibrated devices measured out in calibrated devices for administration.for administration.

Even though these are liquids, it is Even though these are liquids, it is recommended that the patient recommended that the patient follow the administration of the follow the administration of the liquid dosage form with a glassful liquid dosage form with a glassful of water.of water.

The pharmacist must be careful in The pharmacist must be careful in the selection of liquid products the selection of liquid products given the patient’s history and given the patient’s history and other concurrent medicines.other concurrent medicines.

Diabetic patientAntabuse-like activity

Another drug-drowsiness

9. Topical Solutions and 9. Topical Solutions and TincturesTinctures

Generally, the topical solutions empGenerally, the topical solutions employ an aqueous vehicle, whereas the tloy an aqueous vehicle, whereas the topical tinctures characteristically eopical tinctures characteristically employ an alcoholic vehicle.mploy an alcoholic vehicle.

As required, cosolvents or adjuncts tAs required, cosolvents or adjuncts to enhance stabililty or the solubility o enhance stabililty or the solubility of the solute are employed.of the solute are employed.

Most topical solutions and Most topical solutions and tinctures are prepared by simple tinctures are prepared by simple dissolving. However, certain dissolving. However, certain solutions are prepared by solutions are prepared by chemical reaction.chemical reaction.

Because of the nature of the Because of the nature of the active constituents or the active constituents or the solvents, many topical solutions solvents, many topical solutions and tinctures are self-preserved.and tinctures are self-preserved.

(1) Sprays(1) Sprays Sprays may be defined as Sprays may be defined as aqueous or oaqueous or o

leaginous solutionsleaginous solutions in the form of coar in the form of coarse droplets or as finely divided solids tse droplets or as finely divided solids to be applied topically, most usually to o be applied topically, most usually to the nasopharyngeal tract or to the skin.the nasopharyngeal tract or to the skin.

Many commercial sprays are used intrMany commercial sprays are used intranasally to relieve nasal congestion ananasally to relieve nasal congestion and inflammation and to combat infectiod inflammation and to combat infection and containn and contain antihistamines antihistamines, , sympatsympathomimetic agentshomimetic agents, and , and antibiotic substantibiotic substancesances..

Other sprays that are employed agaiOther sprays that are employed against sunburn and heat burn contain lonst sunburn and heat burn contain local anesthetics, antiseptics, skin protcal anesthetics, antiseptics, skin protectants, and antipruritics.ectants, and antipruritics.

Throat sprays containing antiseptics, Throat sprays containing antiseptics, deodorants, and flavorants may be efdeodorants, and flavorants may be effectively employed to relieve conditifectively employed to relieve conditions such as halitosis, sore throat, anons such as halitosis, sore throat, and laryngitis.d laryngitis.

Other sprays treat athlete’s foot Other sprays treat athlete’s foot and other fungal infections.and other fungal infections.

Recently, one-way pump sprays Recently, one-way pump sprays have been developed to deliver have been developed to deliver medication into the nose.medication into the nose.

(2) Aluminum Acetate Topical (2) Aluminum Acetate Topical SolutionSolution

Aluminum acetate is colorless and Aluminum acetate is colorless and has a faint acetous odor and a has a faint acetous odor and a sweetish, astringent taste.sweetish, astringent taste.

It is widely applied topically as an It is widely applied topically as an astringent wash or wet dressing after astringent wash or wet dressing after dilution with 10 to 40 parts of water. dilution with 10 to 40 parts of water.

It is frequently used in various types It is frequently used in various types of dermatologic lotions, creams, and of dermatologic lotions, creams, and pastes.pastes.

(3) Aluminum Subacetate Topical Solu(3) Aluminum Subacetate Topical Solutiontion

Aluminum subacetate Aluminum subacetate （碱式醋酸铝）（碱式醋酸铝）topical solution, is used in prepatatiotopical solution, is used in prepatation of aluminum acetate topical solution of aluminum acetate topical solution.n.

Aluminum acetate topical solution, diAluminum acetate topical solution, diluted first with 20 to 40 parts of water, luted first with 20 to 40 parts of water, is used externally as an astringent wais used externally as an astringent wash and wet dressing.sh and wet dressing.

(4) Calcium Hydroxide Topical (4) Calcium Hydroxide Topical SolutionSolution

Calcium hydroxide topical solution, Calcium hydroxide topical solution, commonly called limewater, must cocommonly called limewater, must contain not less than 140 mg of Ca(OH)ntain not less than 140 mg of Ca(OH)22 in each 100 mL of solution. in each 100 mL of solution.

Calcium hydroxide is less soluble in Calcium hydroxide is less soluble in hot than in cold water, and cool purifhot than in cold water, and cool purified water is the solvent.ied water is the solvent.

The solution should be stored in well-fiThe solution should be stored in well-filled, tightly stoppered containers to delled, tightly stoppered containers to deter the absorption of carbon dioxide anter the absorption of carbon dioxide and should be kept in a cool place to maid should be kept in a cool place to maintain an adequate concentration of disntain an adequate concentration of dissolved solute.solved solute.

The solution is categorized as an The solution is categorized as an astrinastringentgent. For this purpose it is generally e. For this purpose it is generally employed in combination with other inmployed in combination with other ingredients in dermatologic solutions angredients in dermatologic solutions and lotions to be applied topically.d lotions to be applied topically.

(5) Coal Tar Topical Solution(5) Coal Tar Topical Solution

Coal tar topical solution is an alcoholCoal tar topical solution is an alcoholic solution containing 20% coal tar aic solution containing 20% coal tar and 5% polysorbate 80. The final contnd 5% polysorbate 80. The final content is 81 to 86% ethyl alcohol.ent is 81 to 86% ethyl alcohol.

Coal tar is a nearly black viscous liquCoal tar is a nearly black viscous liquid having a characteristic naphthaleid having a characteristic naphthalene-like odor and a sharp, burning tasne-like odor and a sharp, burning taste.te.

It is slightly soluble in water and partIt is slightly soluble in water and partially soluble in most organic solvents,ially soluble in most organic solvents, including alcohol. including alcohol.

Coal tar is a local antieczematic.Coal tar is a local antieczematic.

The solution is used in external treatThe solution is used in external treatment of a wide variety of chronic skiment of a wide variety of chronic skin conditions after dilution with aboun conditions after dilution with about 9 volumes of water, or in combinatit 9 volumes of water, or in combination with other agents in various lotioon with other agents in various lotions, ointments or solutions.ns, ointments or solutions.

(6) Hydrogen Peroxide Topical (6) Hydrogen Peroxide Topical SolutionSolution

Hydrogen peroxide topical solution Hydrogen peroxide topical solution contains 2.5 to 3.5%(w/v) hydrogen contains 2.5 to 3.5%(w/v) hydrogen peroxide, or Hperoxide, or H22OO22 . .

The solution is a clear, colorless The solution is a clear, colorless liquid that may be odorless or have liquid that may be odorless or have the odor of ozone. the odor of ozone.

It usually deteriorates upon long It usually deteriorates upon long standing , forming oxygen and standing , forming oxygen and water.water.

Preservative agents, such as Preservative agents, such as acetanilide, have been found to acetanilide, have been found to retard decomposition.retard decomposition.

Decomposition is enhanced by light Decomposition is enhanced by light and by heat, and for this reason the and by heat, and for this reason the solution should be preserved in solution should be preserved in tight, light-resistant containers, tight, light-resistant containers, preferably at a temperature not preferably at a temperature not exceeding 35℃.exceeding 35℃.

The solution is also decomposed by prThe solution is also decomposed by practically all organic matter and other actically all organic matter and other reducing agents and reacts with oxidireducing agents and reacts with oxidizing agents to liberate oxygen and watzing agents to liberate oxygen and water; metals, alkalies, and other agents cer; metals, alkalies, and other agents can catalyze its decomposition.an catalyze its decomposition.

Hydrogen peroxide solution is categorHydrogen peroxide solution is categorized as a ized as a local anti-infectivelocal anti-infective for use to for use topically on the skin and mucous membpically on the skin and mucous membranes.ranes.

(7) Chlorhexidine Gluconate Soluti(7) Chlorhexidine Gluconate Solutionon

Chlorhexidine gluconate has been eChlorhexidine gluconate has been employed extensively as a broad-spectmployed extensively as a broad-spectrum antiseptic in clinical and veterinrum antiseptic in clinical and veterinarian medicine.arian medicine.

Its spectrum encompasses gram-posiIts spectrum encompasses gram-positive and gram-negative bacteria, incltive and gram-negative bacteria, including Pseudomonas aeruginosa.uding Pseudomonas aeruginosa.

In a concentration of 4% (Hibiclins, StIn a concentration of 4% (Hibiclins, Stuart) it is used as a surgical scrub, hanuart) it is used as a surgical scrub, hand wash, and skin wound and general sd wash, and skin wound and general skin cleanser.kin cleanser.

The most common side effect of chlorThe most common side effect of chlorhexidine is the formation of an extrinshexidine is the formation of an extrinsic yellow-brown stain on the teeth and ic yellow-brown stain on the teeth and tongue after only a few days of use. tongue after only a few days of use.

The developed stain can be periodicalThe developed stain can be periodically removed with dental prophylaxis.ly removed with dental prophylaxis.

(8) Povidone Iodine Topical Soluti(8) Povidone Iodine Topical Solutionon

The agent povidone iodine is a chemical compThe agent povidone iodine is a chemical complex of iodine with polyvinylpyrrolidone.lex of iodine with polyvinylpyrrolidone.

The povidone iodine complex contains approxThe povidone iodine complex contains approximately 10% available iodine and slowly releasimately 10% available iodine and slowly releases it when applied to the skin.es it when applied to the skin.

The preparation is employed topically as a surThe preparation is employed topically as a surgical scrub and nonirritating antiseptic solutigical scrub and nonirritating antiseptic solution, with its effectiveness directly attributable on, with its effectiveness directly attributable to the presence and release of iodine from the to the presence and release of iodine from the complex.complex.

(9) Thimerosal(9) Thimerosal （硫柳汞）（硫柳汞） Topical SoluTopical Solutiontion

Thimerosal is a water-soluble organiThimerosal is a water-soluble organic mercurial antibacterial agent used c mercurial antibacterial agent used topically for its bacteriostatic and mitopically for its bacteriostatic and mild fungistatic properties.ld fungistatic properties.

It is used mainly to disinfect skin and It is used mainly to disinfect skin and as an application to wounds and abraas an application to wounds and abrasions. sions.

It has been applied to the eye, nose, tIt has been applied to the eye, nose, throat, and urethra in dilutions of 1:5hroat, and urethra in dilutions of 1:5000. 000.

It is also used as a preservative for vaIt is also used as a preservative for various pharmaceutical preparations.rious pharmaceutical preparations.

0.1% ThimerosalThimerosal Ethylene diamine solution

Sodium borateMonoethanolamine

The solution must be

maintained in light-resistant

containers

Thimerosal topical solution contains Thimerosal topical solution contains 0.1% thimcrosal.0.1% thimcrosal.

The solution is affected by light and The solution is affected by light and must be maintained in light-resistant must be maintained in light-resistant containers.containers.

10. Vaginal and Rectal 10. Vaginal and Rectal SolutionsSolutions

(1) Vaginal Douches(1) Vaginal Douches Solutions may be prepared from Solutions may be prepared from powpow

ders ders as indicated earlier or from as indicated earlier or from liquliquid solutionsid solutions or or liquid concentratesliquid concentrates. .

In using liquid concentrates , the patIn using liquid concentrates , the patient is instructed to add the prescribient is instructed to add the prescribed amount of concentrate to a certaied amount of concentrate to a certain amount of warm water.n amount of warm water.

The user simply adds the prescribed amount of powdThe user simply adds the prescribed amount of powder to the appropriate volume of warm water and stirs er to the appropriate volume of warm water and stirs until dissolved.until dissolved.

Among the components of douche powders are the foAmong the components of douche powders are the following:llowing:1. Boric acid or sodium borate1. Boric acid or sodium borate

2. Astringents2. Astringents

3. Antimicrobials3. Antimicrobials

4. Quaternary ammonium compounds4. Quaternary ammonium compounds

5. Detergents5. Detergents

6. Oxidizing agents6. Oxidizing agents

7. Salts, e.g. ,sodium citrate, sodium chloride7. Salts, e.g. ,sodium citrate, sodium chloride

8. Aromatics, e.g. , menthol, thymol.8. Aromatics, e.g. , menthol, thymol.

(2) Retention Enemas(2) Retention Enemas

A number of solutions are administered A number of solutions are administered rectally for the local effects of the rectally for the local effects of the medication or for systemic absorption.medication or for systemic absorption.

Clinically effective blood levels of the agents Clinically effective blood levels of the agents are usually obtained within 30 minutes are usually obtained within 30 minutes following rectal instillation.following rectal instillation.

hydrocortisoneaminophylline

(3) Evacuation Enemas(3) Evacuation Enemas

Rectal enemas are used to cleanse the bowel.Rectal enemas are used to cleanse the bowel. The agents present are The agents present are - solutions of sodium phosphate and sodium bsolutions of sodium phosphate and sodium b

iphosphate iphosphate - glycerin and docusate potassiumglycerin and docusate potassium- light mineral oillight mineral oil

The patient should be advised to gently The patient should be advised to gently insert the tip of the product with steady insert the tip of the product with steady pressure and be told that it is not absolutely pressure and be told that it is not absolutely necessary to squeeze all of the contents out necessary to squeeze all of the contents out of the disposable plastic bottle.of the disposable plastic bottle.

The patient should be told that the product The patient should be told that the product will most probably work within 5 to 10 will most probably work within 5 to 10 minutes.minutes.

11. Topical Tinctures11. Topical Tinctures

(1) Iodine Tincture(1) Iodine Tincture

2% iodine crystals2.4% sodium iodide

AlcoholPurified water

I2+NaINaI3

This reaction prevents the formation of ethyl iodide from theinteraction between iodine and thealcohol, which would result in theloss of the antibacterial activity of

The tincture.

The tincture is a popular local The tincture is a popular local anti-inanti-infective agentfective agent applied to the skin, is u applied to the skin, is useful in delineating the application oseful in delineating the application over the affected skin area.ver the affected skin area.

The tincture should be stored in a tigThe tincture should be stored in a tight container to prevent loss of alcohoht container to prevent loss of alcohol. l.

(2) Compound Benzoin Tincture(2) Compound Benzoin Tincture

Maceration in alcohol of 10% benzoin24% aloe, storax and tolu balsam

The tincture is categorized as a protectant. The tincture is categorized as a protectant. It is used to protect and toughen skin in the treIt is used to protect and toughen skin in the treatment of atment of bedsores, ulcers, cracked nipples, and fissures bedsores, ulcers, cracked nipples, and fissures of the lips of the lips and anus.and anus.

It is also commonly used as an inhalaIt is also commonly used as an inhalant in bronchitis and other respiratornt in bronchitis and other respiratory conditions.y conditions.

Compound tincture of benzoin serveCompound tincture of benzoin serves as a delivery vehicle of podophyllus as a delivery vehicle of podophyllum in the treatment of venereal warts.m in the treatment of venereal warts.

(3) Thimerosal Tincture(3) Thimerosal Tincture

The commercial The commercial preparation is colored preparation is colored orange red and has orange red and has greenish fluorescence. greenish fluorescence.

The red stain it leaves on The red stain it leaves on the skin defines the area the skin defines the area of application. of application.

It is a commonly used It is a commonly used household antiseptic for household antiseptic for application to abrasions application to abrasions and cuts and also in and cuts and also in preparation of patients preparation of patients for surgery.for surgery.

0.1% ThimerosalThimerosal Monoethanolamine

Distilled waterAcetone

50% alcohol

12. Special application solutions12. Special application solutions

(1) nasal preparations(1) nasal preparations The vast majority of preparations The vast majority of preparations

intended for intranasal use contain intended for intranasal use contain adrenergic agentsadrenergic agents and are and are employed for their decongestant employed for their decongestant activity on the nasal mucosa.activity on the nasal mucosa.

Nose dropsSpraysJellies

Nasal decongestant solutionsNasal decongestant solutions

Most nasal decongestant solutions areMost nasal decongestant solutions are aqueous preparationsaqueous preparations rendered isotonic to nasal fluids rendered isotonic to nasal fluids

(approximately equivalent to 0.9% (approximately equivalent to 0.9% sodium chloride),sodium chloride),

buffered to maintain drug stability buffered to maintain drug stability (pH5.5(pH5.56.5)6.5)

stabilized and preserved as required.stabilized and preserved as required.

Most of the adrenergic drugs Most of the adrenergic drugs used in nasal decongestant used in nasal decongestant solutions are synthetic solutions are synthetic compounds epinephrine.compounds epinephrine.

Most solutions for nasal use are Most solutions for nasal use are packaged in dropper bottles or in packaged in dropper bottles or in plastic spray bottles, usually plastic spray bottles, usually containing 15 to 30 ml of containing 15 to 30 ml of medication.medication.

The concentration of adrenergic agent The concentration of adrenergic agent is ranging from about 0.05 to 1.0%.is ranging from about 0.05 to 1.0%.

Nasal decongestant solutions are Nasal decongestant solutions are employed in the treatment of rhinitis employed in the treatment of rhinitis of the common cold and for vasomotor of the common cold and for vasomotor and allergic rhinitis including hay and allergic rhinitis including hay fever, and for fever, and for sinusitissinusitis..

The frequent use or their use for The frequent use or their use for prolonged periods may lead to prolonged periods may lead to chronic chronic edemaedema of the nasal mucosa. Thus, they of the nasal mucosa. Thus, they are best used for short periods (no are best used for short periods (no longer than 3 to 5 days).longer than 3 to 5 days).

（（ 22 ）） Otic SolutionOtic Solution Ear preparations are usually placed iEar preparations are usually placed i

n the ear canal by n the ear canal by dropsdrops or in small a or in small amounts for the removal of mounts for the removal of excessive excessive cerumencerumen (ear wax) or for the treatme (ear wax) or for the treatment of nt of ear infectionsear infections, , inflammationinflammation, or , or painpain..

Cerumen-removing solutionsCerumen-removing solutionsLight mineral oil

Vegetable oilsHydrogen peroxide

Solution of Synthetic surfactants

1) Triethanolamine polypeptide oleate-condensate in propylene glycol

2) Carbamide peroxide in glycerin/Propylene glycol

Commercial products

Anti-infective, anti-inflammatory, anAnti-infective, anti-inflammatory, and analgesic ear preparationsd analgesic ear preparations

Drugs used topically in the ear for thDrugs used topically in the ear for their antiinfective activity includeeir antiinfective activity include

chloramphenicolchloramphenicol colistin sulfatecolistin sulfate neomycinneomycin polymyxin B sulfatepolymyxin B sulfate nystatinnystatin

Anti-inflammatory agents-Hydrocortisone

-Dexamethasone sodium phosphate-Acetic acid (2%) in aluminum

acetate solution-Boric acid (2.75%) in isopropyl alcohol

Topical analgesics antipyrine

local anesthetic benzocaine in a vehicle of propylene glycol

or anhydrous glycerin

PreservationPreservation Chlorobutanol (0.5%)Chlorobutanol (0.5%) Thimerosal (0.01%)Thimerosal (0.01%) Combinations of the parabensCombinations of the parabensAntioxidants Antioxidants Sodium bisulfiteSodium bisulfiteStabilizersStabilizers

13. Miscellaneous Solutions13. Miscellaneous Solutions

(1) Aromatic Waters(1) Aromatic Waters Aromatic waters are clear, aqueous sAromatic waters are clear, aqueous s

olutions saturated with volatile oils oolutions saturated with volatile oils or other aromatic or volatile substancr other aromatic or volatile substances.es.

Aromatic waters may be used for perAromatic waters may be used for perfuming and/or flavoring.fuming and/or flavoring.

(2) Diluted Acids(2) Diluted Acids Diluted acids are aqueous solutions preDiluted acids are aqueous solutions pre

pared by diluting the corresponding copared by diluting the corresponding concentrated acids with purified water.ncentrated acids with purified water.

The strength of a The strength of a diluted aciddiluted acid is general is generally expressed on a percent ly expressed on a percent weght-to-volweght-to-volume (% w/v)ume (% w/v) basis, that is, the weight in basis, that is, the weight in grams of solute per 100 mL of solution, grams of solute per 100 mL of solution,

whereas the strength of a whereas the strength of a concentrated concentrated acidacid is generally expressed in terms of is generally expressed in terms of percent percent weight to weight (% w/w)weight to weight (% w/w), whic, which indicates the number of grams of solh indicates the number of grams of solute per 100 g of solution.ute per 100 g of solution.

To prepare a diluted acid from a To prepare a diluted acid from a concentrated one, it is necessary concentrated one, it is necessary first to calculate the amount of first to calculate the amount of solute required in the diluted solute required in the diluted product. product.

Then the amount of concentrated Then the amount of concentrated acid required to supply the needed acid required to supply the needed amount of solute can be determined.amount of solute can be determined.

To illustrate, concentrated hydrochloric To illustrate, concentrated hydrochloric acid (HCl) contain not less than 35 g and acid (HCl) contain not less than 35 g and not more than 38 g of solute per 100 g of anot more than 38 g of solute per 100 g of acid and therefore is considered to be, on tcid and therefore is considered to be, on the average, 36.5% w/w in strength. he average, 36.5% w/w in strength.

Diluted HCl contains 9.5 to 10.5 g of solutDiluted HCl contains 9.5 to 10.5 g of solute per 100 mL of solution and is therefore e per 100 mL of solution and is therefore considered to be approximately 10% w/v considered to be approximately 10% w/v in strength. in strength.

If one wished to prepare 100mL of the dilIf one wished to prepare 100mL of the diluted acid from the concentrated acid, onuted acid from the concentrated acid, one woulde would

require 10 g of solute. The amount of concrequire 10 g of solute. The amount of concentrated HCl required to supply this amouentrated HCl required to supply this amount of solute may be calculated by the follont of solute may be calculated by the following proportion: wing proportion:

Thus, 27.39 g of concentrated acid is requiThus, 27.39 g of concentrated acid is required to supply 10 g of solute needed for the red to supply 10 g of solute needed for the preparation of 100 mL of the diluted acid.preparation of 100 mL of the diluted acid.

Concentrated sulfuric acid 95-98% (w/w)Concentrated nitric acid 69-71% (w/w)

Concentrated phosphoric acid 85-88% (w/w)

(3) Spirits(3) Spirits Spirits are alcoholic or hydroalcoholic Spirits are alcoholic or hydroalcoholic

solutions of volatile substances. solutions of volatile substances. Generally, the alcoholic concentration Generally, the alcoholic concentration

of spirits is rather high, usually over 60of spirits is rather high, usually over 60%. %.

Because of the greater solubility of aroBecause of the greater solubility of aromatic or volatile substances in alcohol tmatic or volatile substances in alcohol than in water, spirits can contain a greathan in water, spirits can contain a greater concentration of these materials thaer concentration of these materials than the corresponding aromatic waters. n the corresponding aromatic waters.

Spirits may be used pharmaceutically Spirits may be used pharmaceutically as as flavoring agentsflavoring agents and medicinally and medicinally for the for the therapeutic value of the therapeutic value of the aromatic solutearomatic solute. .

For medicinal purposes, spirits may For medicinal purposes, spirits may be taken be taken orallyorally, applied , applied externallyexternally, or , or used by used by inhalationinhalation, depending upon , depending upon the particular preparation. the particular preparation.

When taken orally, they are generally When taken orally, they are generally mixed with a portion of water to mixed with a portion of water to reduce the pungency of the spirit. reduce the pungency of the spirit.

14. Nonaqueous Solutions14. Nonaqueous Solutions

(1) Liniments (1) Liniments （搽剂）（搽剂） Liniments are alcoholic or oleaginouLiniments are alcoholic or oleaginou

s solutions or emulsions of various ms solutions or emulsions of various medicinal substances intended to be ruedicinal substances intended to be rubbed on the skin. bbed on the skin.

Liniments are useful when rubefacieLiniments are useful when rubefacient, counterirritant, or penetrating actnt, counterirritant, or penetrating action is desired; oleaginous liniments aion is desired; oleaginous liniments are employed primarily when massage re employed primarily when massage is desired.is desired.

All liniments should bear a label All liniments should bear a label indicating that they are suitable indicating that they are suitable only for external use and must only for external use and must never be taken internally. never be taken internally.

Oleaginous linimentsThe solvent may be fixed oil such as

almond oilpeanut oilsesame oil

cottonseed oilvolatile substance such as winter-green oil or turpentine

(2) Collodions(2) Collodions （火棉胶）（火棉胶） Collodions are liquid preparations comCollodions are liquid preparations com

posed of pyroxylin posed of pyroxylin （硝酸纤维素）（硝酸纤维素） dissoldissolved in a solvent mixture usually composved in a solvent mixture usually composed of alcohol and ether with or without ed of alcohol and ether with or without added medicinal substances.added medicinal substances.

Pyroxylin, like collodions, is exceedinglPyroxylin, like collodions, is exceedingly flammable and must be stored away fry flammable and must be stored away from flame in well-closed containers, protom flame in well-closed containers, protected from light.ected from light.

Collodions are intended for external use.Collodions are intended for external use.

CollodionCollodion Collodion is a clear or slightly opalesCollodion is a clear or slightly opales

cent viscous liquid .cent viscous liquid . The product is capable of forming a The product is capable of forming a

protective film on application to the protective film on application to the skin and the volatilization of the solvskin and the volatilization of the solvent. The flim is useful in holding the ent. The flim is useful in holding the edges of an incised wound together. edges of an incised wound together.

However, its presence on the skin is However, its presence on the skin is uncomfortable because of its inflexiuncomfortable because of its inflexible nature.ble nature.

Flexible collodion Flexible collodion （弹性火棉胶）（弹性火棉胶） Flexible collodion is prepared by addFlexible collodion is prepared by add

ing 2% camphor and 3% castor oil to ing 2% camphor and 3% castor oil to collodion. collodion.

The castor oil renders the product fleThe castor oil renders the product flexible, permitting its comfortable use xible, permitting its comfortable use over skin areas that are normally moover skin areas that are normally moved, such as fingers and toes. The caved, such as fingers and toes. The camphor makes the product waterproomphor makes the product waterproof. f.

Salicylic acid coilodionSalicylic acid coilodion It is used for its keratolytic effects, espeIt is used for its keratolytic effects, espe

cially in the removal of corns from the tcially in the removal of corns from the toes. oes.

The product should be applied one drop The product should be applied one drop at a time on the corn or wart, allowing tiat a time on the corn or wart, allowing time to dry before the next drop is added. me to dry before the next drop is added.

Proper tightening and storage of the proProper tightening and storage of the product after use are absolutely necessary duct after use are absolutely necessary because of the volatility of the vehicle.because of the volatility of the vehicle.

15. Extraction Methods for Preparing Solutions15. Extraction Methods for Preparing Solutions

Certain pharmaceutical Certain pharmaceutical preparations are prepared by preparations are prepared by extraction, that is, by withdrawal extraction, that is, by withdrawal of desired constituents from of desired constituents from crude drugs through the use of crude drugs through the use of selected solvents in which the selected solvents in which the desired constituents are soluble.desired constituents are soluble.

WaterHydroalcoholic mixturesHydroalcoholic mixtures

GlycerinGlycerin

Methods of ExtractionMethods of Extraction

The principal methods of drug The principal methods of drug extraction are maceration and extraction are maceration and percolation. percolation.

Generally, the method of extraction Generally, the method of extraction selected for a given drug depends on selected for a given drug depends on several factors, including the nature several factors, including the nature of the crude drug, its adaptability to of the crude drug, its adaptability to each of the various extraction each of the various extraction methods, and the interest in methods, and the interest in obtaining complete or nearly obtaining complete or nearly complete extraction of the drug.complete extraction of the drug.

(1) Maceration (1) Maceration （浸渍）（浸渍） It is a process in which the properly It is a process in which the properly

comminuted drug is permitted to soacomminuted drug is permitted to soak in the menstruum until the cellular k in the menstruum until the cellular structure is softened and penetrated structure is softened and penetrated by the menstruum and the soluble coby the menstruum and the soluble constituents are dissolved.nstituents are dissolved.

For drugs containing little or no celluFor drugs containing little or no cellular material, such as benzoinlar material, such as benzoin （安息（安息香）香） , aloe, aloe （芦荟）（芦荟） , and tolu, and tolu （妥鲁香（妥鲁香 ） ） , which dissolve almost completel, which dissolve almost completely in the menstruum, maceration is thy in the menstruum, maceration is the most efficient method of extraction.e most efficient method of extraction.

Maceration is usually conducted at a tMaceration is usually conducted at a temperature of 15℃ to 20 ℃ for 3 days emperature of 15℃ to 20 ℃ for 3 days or until the soluble matter is dissolveor until the soluble matter is dissolved.d.

(2) Percolation(2) Percolation （渗漉）（渗漉） It may be described generally as a It may be described generally as a

process in which a comminuted drug process in which a comminuted drug is extracted of its soluble constituents is extracted of its soluble constituents by the slow passage of a suitable by the slow passage of a suitable solvent through a column of the drug.solvent through a column of the drug.

The drug is packed in a special The drug is packed in a special extraction apparatus termed a extraction apparatus termed a percolator, with the collected percolator, with the collected extractive called the percolate.extractive called the percolate.

Most drug extractions are performed Most drug extractions are performed by percolation .by percolation .

In the process of percolation the flow In the process of percolation the flow of the menstruum over the drug coluof the menstruum over the drug column is generally downward to the exit omn is generally downward to the exit orifice, drawn by the force of gravity as rifice, drawn by the force of gravity as well as the weight of the column of liqwell as the weight of the column of liquid. uid.

In certain specialized and more sophisIn certain specialized and more sophisticated percolation apparatus, additioticated percolation apparatus, additional pressure on the column is exerted nal pressure on the column is exerted with positive air pressure at the inlet awith positive air pressure at the inlet and suction at the outlet or exit.nd suction at the outlet or exit.

Percolators for drug extraction vary Percolators for drug extraction vary greatly as to their shape, capacities, greatly as to their shape, capacities, composition, and, most important utcomposition, and, most important utility.ility.

Percolators employed in the large-scPercolators employed in the large-scale industrial preparation of extractiale industrial preparation of extractive are generally stainless steel or glave are generally stainless steel or glasslined metal vessels that vary greatlsslined metal vessels that vary greatly in size and in operation.y in size and in operation.

Percolation on a small scale generallPercolation on a small scale generally involves the use of glass percolatory involves the use of glass percolators of various shapes for extraction of ss of various shapes for extraction of small amounts (perhaps up to 1000 g) mall amounts (perhaps up to 1000 g) of crude drug.of crude drug.

The cylindrical percolator is particulThe cylindrical percolator is particularly suited to the complete extractioarly suited to the complete extraction of drugs with a minimal expenditun of drugs with a minimal expenditure of menstruum.re of menstruum.

Example preparations prepared bExample preparations prepared by extraction processesy extraction processes

FluidextractsFluidextracts Extracts Extracts

Questions Questions

1.1. How to prepare purified water?How to prepare purified water?2.2. What solvents are commonly used fWhat solvents are commonly used f

or liquid preparations?or liquid preparations?3.3. What are elixirs and tinctures? What are elixirs and tinctures? 4.4. Please give examples to explain hoPlease give examples to explain ho

w to prepare medicated elixirs and tw to prepare medicated elixirs and tinctures?inctures?