Solid Dosage Form III (Tablet coating, packaging)

Pietradewi Hartrianti, PhD

“Tablet coating is the application of coating

material to the exterior of a tablet with the intention of

conferring benefits and properties to a dosage form over the uncoated variety.

Solid Dosage Form II : Tablet coating

Mask Bitter taste, unpleasant odour

Protecting the drug from physical and chemical degradation

increase Stability.

Handling & ease of ingesting by patients.

Mechanical protection from breakage.

Avoid Light incompatibility.

Protection from Environmental Oxidation.

In- elegent core.

modify the drug release profile.

Product identity.

Coating purposes

Increase packaging speed

Reduces damage during the packaging process

Printing efficiency and clarity

Product identification

Reduced changeover and clean down time

Reduces operator exposure to active substances

Coating for

processing

• Allows product to stand out from the competition

• Give colour and tablet shape for branding and trademark substances

Coating for marketing

• Patient compliance is affected by a product’s :

• Ease of Use

• Identity

• Efficacy

• Taste

• Odour

Coating for Consumers

Coating for

marketing and

consumer

•Light

•Moisture

•Oxidation

Protect from

Coating for

stability

• No functional coat.

• Provide release of drug at various GI sites depending on pH.

• Change rate of release of active e.g. control rate of active release over 24 hours.

Coating for release

Sugar coating

Film coating

Enteric coating

Controlled release coating

Specialized coating

• Compressed coating

• Electrostatic coating

• Dip coating

• Vacuum film coating

Type of Coating

Process of Tablet CoatingProcess of tablet coating

Mechanical and Physical Strength

Smooth surface

Physical shape (must be spherical/biconvex)

Chemical nature of tablet ingredients

Hygroscopicity

Tablet properties

for coating

• The standard coating pan

• Depending on drying efficiency

• Pellegrini system

• Immersion-sword system

• Immersion –tube system

• The perforated coating pan

• Accela-coata

• Hi-coater systems

• Driacoater

• Glatt coater

• The fluidized bed (Air suspension) coater.

Three types of equipments

Type of coating

equipment

Air Capacity:

• Quantity of water or solvent removed during coating process

• Depends on :

• 1. Quantity of air flow through tablet bed,

• 2. Temperature of air,

• 3. water content of inlet air.

Coating Composition:

• Inlet air-heated, exhaust air- cool.

• Drying of film- rate of application

• Thin rapidly drying formulations dry quickly on the tablet surface allowing constant application by efficient atomization of coating solution

Parameters of coating

process

Tablet surface area:

• Size and presence of debossed features affects coating conditions

• Total surface area per unit weight decreases from smaller to larger tablets

• For same thickness of film, smaller tablets requires more coating composition as compared with larger tablets

• Size of atomized coating droplets must be smaller and better controlled as the features to be coated become smaller.

Equipment efficiency,

• 𝐶𝑜𝑎𝑡𝑖𝑛𝑔𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦,

• E =𝑁𝑒𝑡 𝑖𝑛𝑐𝑟𝑒𝑎𝑠𝑒 𝑖𝑛 𝑐𝑜𝑎𝑡𝑒𝑑 𝑡𝑎𝑏𝑙𝑒𝑡 𝑤𝑒𝑖𝑔ℎ𝑡

𝑇𝑜𝑡𝑎𝑙 𝑛𝑜𝑛𝑣𝑜𝑙𝑎𝑡𝑖𝑙𝑒 𝑐𝑜𝑎𝑡𝑖𝑛𝑔 𝑤𝑒𝑖𝑔ℎ𝑡 𝑎𝑝𝑝𝑙𝑖𝑒𝑑 𝑡𝑜 𝑡𝑎𝑏𝑙𝑒𝑠

Parameters of coating

process

Facility and Ancillary Equipment

• Facility should meet to requirement of cGMP

• Adequate space for equipment, processing, in-process storage

• Safety requirements depending on nature of solvent- electrical explosion-proofing, specialized ventilation

• Exhaust air treatment to recover solvent or to prevent entry in to atmosphere

• Federal EPA defines limits of organic solvents and particulate allowed in atmosphere

• Aqueous based coating is advantageous

• Other Equipments

• Tanks, filters, mixers, mills, jacketed tanks, portable pressure tanks or pumping systems.

Parameters of coating

process

• the most conventional multistep coating process.

• this process involves application of sugar (sucrose) based coating solution to the tablets.

• carried out in coating pans having variable capacities & mounted at an angel of 40o

Sugar Coating

Sugar Coating

Advantages of S.C.

• cheap

• safe coating material

• cheap coating machine

• good patient compliance

• can be reprocessed

• require less hardness core

• Mask taste and odor

Disadvantages of S.C

• time consuming process. (hours to few days)

• high weight gain.

• Increase in packaging & shipping.

• required trained personnel.

• Imprinting problems.

Advantages and disadvantages

Tablet Coating Process

• Final production step on which quality of product may be judged

Sugar Coating

• Steps involves,

• Sealing,

• Subcoating

• Syruping (Smoothing/Grossing)

• Coloring

• Finishing

• Polishing

Coating process

Seal coating

• To prevent moisture penetration into tablet core

• Specially in pan-ladling process in which localized overwetting of portion of tablet bed occur

• Affects disintegration and dissolution time due to polymerization on aging

• Such effect is not reported

Sugar coating

Subcoating

•To round the edges and build up size .

•Subcoating Steps

•Sticky binder solution Dusting of subcoating powders Drying

Sugar coating

Syruping (Smoothing/ Grossing)

• To cover and fill in the imperfections in tablet surface caused by subcoating

• First syrup coat contains some suspended powders i.e. grossing syrups

Sugar coating

Coloring

•To impart desired color

•Dilute colorants– tinted base– uniform coating

•Syrup solution containing dye applied until final size and color are achieved

Sugar coating

Finishing

• Final syrup coating step

• Few clear coats of syrup may be applied

Polishing

• Desired luster is obtained in this final step

• Clean standard coating pan, canvas-lined coating pans

• Application of powdered wax or warm solution of waxes in suitable volatile solvent

Sugar coating

Sugar coating

• Modern approach to coating Tablets, Capsules, Or Pellets by surrounding them with a thin layer of polymeric material.

• Single stage process, which involves spraying a coating solution.

• The solution is sprayed onto a rotating tablet bed followed by drying, which facilitates the removal of the solvent leaving behind the deposition of thin film of coating materials around each tablet.

Film coating

• The technique involved in enteric coating is protection of the tablet core from disintegration in the acidic environment of the stomach by employing pH sensitive polymer, which swell or solubilize in response to an increase in pH to release the drug.

• Aims of Enteric protection:– Protection of active ingredients, from

the acidic environment of the stomach.

– Protection from local irritation of the stomach mucosa.

– Release of active ingredient in specific target area within gastrointestinal tract.

Enteric coating

Film coating and sugar coating shares the same equipments and process parameters

Two methods : Pan-Pour and Pan-Spray

Film coating

Pan-Pour method

• Same as that of pan-pour sugar coating

• Method is relatively slow and relies heavily on skill and technique of operator

• Aqueous based film coating is not suitable due to localized over-wetting

Pan-Spray method

• Use of automated spraying system

Film Coating

• To ensure the consistent product quality, certain elements of process need to be controlled regardless of coating pan system

• The variables to be controlled in pan-spray film coating process are:

Pan variables

• Pan design/ baffling

• Speed

• Pan load

Process air

• Air quality

• Temperature

• Airflow rate/ volume/ balance

Spray variables

• Spray rate

• Degree of atomization

• Spray pattern

• Nozzle-to-bed distance

Process Variables

Criteria :

• Solubility in solvent

• Solubility required for intended use

• Capacity to produce elegant looking product

• Stability with heat, light, moisture, air, substrate.

• Essentially no color, taste, odor

• Compatibility with common coating solution additives

• Nontoxic , therapeutically inert and ease of application to the particles or tablets

• Resistance to cracking, and provision of adequate moisture, light, odor, or drug sublimation barrier when desired

• No bridging or filling of the debossed tablet surfaces by the film former

• Ease of printing procedures on high-speed equipment

Material used in

film coating

Film Formers

1 . Nonenteric Materials

• HPMC,

• MHEC,

• EC,

• HPC,

• Povidone,

• SCMC,

• PEG,

• Acrylate Polymers

Coating excipient

Enteric Materials

Reasons for enteric

• Protect acid labile drugs from gastric fluid

• e.g. enzymes, ATBTs

• Prevent gastric distress or nausea due to irritation from drug, e.g. Sodium Salicylate

• To deliver drugs for local action in intestines, e.g. Intestinal antiseptic (Kanamycin)

• For drugs optimally absorbed in small intestine

• Provide delayed release component for repeat-action tablets

Material should have following properties

• Resistance to gastric fluids

• Ready susceptibility or permeability to intestinal fluids

• Stability with coating composition and drug substrate

• Stability alone and in coating solution

• Formation of continuous film

• Nontoxicity, Low cost

• Ease of application without special equipments

• Ability to be printed or to allow film to be applied to debossed tablets

Coating excipient

Enteric materials (phtalate polymers)

• CAP,

• Acrylate Polymers

• HPMCP

• PVAP

B. Solvents

C. Plasticizers

• “ Internal ” or “ External ” techniques

D. Colorants

E. Opaquant-Extenders

F. Miscellaneous Coating Solution Components

Coating excipient

Quality Control

Stability Testing

Film Defects

Coating evaluatio

n

• For coated tablet, coating equipment is needed

• The standard coating pan

• Depending on drying efficiency

• Pellegrini system

• Immersion-sword system

• Immersion –tube system

• The perforated coating pan

• Accela-coata

• Hi-coater systems

• Driacoater

• Glatt coater

• The fluidized bed (Air suspension) coater.

Three types of equipments

Coating equipmen

t

Conventional pan

• 8-60 inches diameter revolving on its horizontal axis.

• Heated air is directed into the pan and onto the tablet bed surface.

• Exhausted by means of ducts positioned through the front of the pan

• Drying efficiency is achieved by,

• Pellegrini pan :

• Has a baffled pan and diffuser for uniform distribution of drying air.

• Enclosed and automated

2. Immersion-sword system

• Drying air through perforated metal sword immersed in the tablet bed.

• Upward flow through bed.

• Spray onto the bed surface

3. Immersion-tube system

• Tube immersed in tablet bed

• Delivers heated air and coating solution through spray built in the tip of tube

• Flows upward and exhausted by a conventional duct.

Perforated pan system:

• Perforated drum rotates on its horizontal axis in an enclosed housing.

• Accela-Coata and Hi-coater system

• Drying air is directed in to drum , is passed through bed , and is exhausted through perforations in to drum.

• Accela-Coata :

• pan is fully perforated

• contains mixing blades.

• Inlet air is by a plenum in contact with the top of the pan.

• air is exhausted by a plenum located below the pan.

• Hi- coater

• consists of four perforated segments which are perfendicular to each other

• each of these perforations acts as an opening for air outlet which is fixed to the exterior of the pan surface.

• drying air is introduced into pan through an opening located on inside periphery of top of the pan.

Accela-coata

Hi-Coater

Driacoater :

• Introduces drying air through hollow perforated

• ribs located inside periphery of the drum.

• With rotating pan, ribs dip into bed

• Drying air passes up through and fluidizes bed

• Exhaust is from back of the pan

Glatt coater :

• Drying air directed from inside the drum

• through bed and out an exhaust duct

• With an optional split-chambered plenum

• drying air can be directed in the reverse manner

• Several air flow configurations are possible.

3. Fluidized bed (Air suspension system)

• Highly efficient

• Fluidization of tablet bed is achieved in a columnar chamber by the upward flow of drying air.

Spray application System

Two basic types of spray system differ in manner in which atomization of liquid is achieved

• High-pressure, airless

• High pressure liquid (250-3000psig) through a small orifice (.009”- .020” id)

• Degree of automization- fluid pressure, orifice size, viscosity.

• Low-pressure, air-automized

• Low pressure liquid (5-50psig) through a large orifice (.020”-.060” id)

• Degree of automization- fluid pressure, orifice size, viscosity, air pressure, air cap design.

BLISTER PACKAGING MACHINE

• In pharmaceutical industry Blister Packaging Machines are used for the packing tablets, capsules, pills and other similar products packing.

• pre-formed plastic packaging commonly used as unit dose packaging for pharmaceuticals such as tablets, capsules or lozenges.

• Blister packs consist of two principal components :

• 1) The cavity made from either plastic or aluminium.

• 2) the lidding, made from paper board, paper, plastic or aluminium.

• The cavity contains the product and the lidding seals the product in the package. There are two types of forming the cavity into a base web sheet: thermoforming and cold forming

Packaging for Solid

dosage form

– The packing process start with the capsules or tablets being loaded into a hopper and then into a feeder, which in turn can either be linear feeder or a brush box feeder depending on the shape of the product and also the material to be used.

– Heated rollers in the machine use different plastic films to form blisters that are subsequently filled with tablets.

– Some machines make use of alluminium foil to form blisters

Blistering process

• Machines are manufactured according to the size, depth and material used to form blisters.

• After tablets have been inserted in the formed blisters, cavities are heat sealed using foil.

• Blister Sealing Machines are used to seal filled plastic blister to a piece of coated carton board, by heat.

• The blister is kept in the sealing die which has the same shape as that of the cavity. The cavities are then filled and sealed by a foil using heat.

• Blister Trimming Machines are used for cutting, trimming the sealed blister or formed blister packs

Blistering process

• PVC(Polyvenyl Chloride)

• PCTFE (Polychlorotrifluroethylene)

• COC (Cyclic olefin copolymers )

• PVDC(Polyvenyledene chloride)

• PP(polypropylene)

• PE (polyethylene),

• PETg (glycol-modified polyethylene terephthalate)

Materials used in blister

packaging

• Strip packaging

• alternative form of pack for a unit dosage. It is a method of enclosing the product concerned between the two web of material so that each is contained between separate compartment. Two web of material may not be necessary to be identical.

Strip packagin

g

• Find :

– Compressed coating

– Electrostatic coating

– Dip coating

– Vacuum film coating

• Find evaluation of tablet coating based on FI V/ IV on

– Dissolution

– Disintegration

In class assignmen

t

• Ansel, Pharmaceutical Dosage Form and Drug Delivery System

• Lachman/Lieberman Theory and Practice of Industrial Pharmacy

• AultonReferences