brief introduction to multiple emulsion, microemulsion,

BRIEF INTRODUCTION TO MULTIPLE EMULSION,

MICROEMULSION, NANOEMULSION & NANOSUSPENSION

Presented by- Md . Shariq AnsariB.Pharm 5th sem

Under the guidance: Mr. Dilip Kr. Patel

CONTENT

• Defination• Emulsion• Types Of Emulsions• Identification test for emulsion• Emulsifying agent• Method of preparation of emulsion• Microemulsion• Nanoemulsion• Nanosuspension

DEFINATION

• An Emulsion is a mixture of two or more liquids that are normally Immiscible.

OR• Emulsion, is a mixture of two or more liquids in which

one is present as droplets, of microscopic or ultramicroscopic size, distributed throughout the other.

OilOil

WaterWater

Oil

Water

Agitation

Separate rapidly into two clear defined layers

OilOil

WaterWater

Oil

Water

Agitation

Separate rapidly into two clear defined layers

Emulsion

Microemulsion

Nanoemulsion

Thermodynamically unstable Opaque High energy required to form

Thermodynamically stable Clear It forms spontaneously

Thermodynamically or kinetically stable Clear High shear application to form

Int. J. Nanomed. 2014,9,pp 1-8

Internal Phase or External Phase in Emulsions:

The dispersed liquid is known as the Internal or Discontinuous phase.

whereas the dispersion medium is known as the External or Continuous phase. 

Based on size of liquid droplets: 0.2 – 50 mm Macroemulsions 0.01 – 0.2 mm Microemulsions

IDENTIFICATION TEST FOR EMULSIONS:

By using Naked eye, it is very difficult to differentiate between o/w or w/o emulsions. Thus, the following methods have been used to identify the type of emulsions.

1) Dye Test 2) Dilution Test3) Electrical conductivity Test4) Fluorescence Test.

EMULSIFYING AGENT:• Emulsions are stabilized by adding an emulsifying agent. • These agents have both a hydrophilic and a Lipophilic part

in their chemical structure.• All emulsifying agents get adsorbed onto the Oil : water

interface to provide a protective barrier around the dispersed droplets.

• In addition to this protective barrier, emulsifiers stabilize the emulsion by reducing the interfacial tension of the system.

• E.g. agar, albumin, cholic acid, glycerol, gums, soaps, casein, ox bile extract.

METHODS OF PREPARATION OF EMULSIONS:

• Commercially, emulsions are prepared in large volume mixing tanks and refined and stabilized by passage through a colloid mill or homogenizer. Extemporaneous production is more concerned with small scale methods.

1) Dry Gum Methods2) Wet Gum Methods3) Bottle Method

MICROEMULSION• Micro Emulsions are dispersions of oil and water made

with surfactant, co-surfactant molecules. In many respects, they are small-scale versions of emulsions. However, the droplet sizes are very small, typically 100 A, about 100 times smaller than typical emulsion droplet sizes.

W/O O/W

OR

• “Microemulsions are liquid dispersions of water and oil that are made homogenous, transparent (or translucent) and thermodynamically stable by the addition of relatively large amounts of a surfactant and a co-surfactant and having diameter of the droplets in the range of 100 – 1000 A (10 – 100 nm).

(Figure : Microemulsion Structure)

Advantages of Microemulsions:

.These are thermodynamically stable . . Require minimum energy for formation. . Easy of manufacturing . . Improved drug solubilization and bioavailability. . Wide applications in colloidal drug delivery systems. . The formation of microemulsion is reversible.  . Improve the efficacy of a drug & Minimum side effects.

Disadvantages of Microemulsions:

•Use of a large concentration of surfactant and co-surfactants.• Limited solubilizing capacity for high-melting substances.• The surfactant must be nontoxic for using pharmaceutical applications.• Microemulsion stability is influenced by environmental parameters such as temperature and pH.

NANOEMULSIONS

• Dispersion of two immiscible liquids stabilized by a surfactant

• Thermodynamically and kinetically stable

• Droplets from 5 to 200 nm

Nanoemulsions - Applications

Agriculture

Cleaning products

Cosmetic

Pharmaceutic

Biomedical

Nanoemulsions - Drug DeliveryAdvantages Increase drug loading Enhance drug solubility Bioavailability Controlled drug delivery Protection of drug

Disadvantages Expensive process Stability Solubility Lack of understanding of interfacial chemistry

J. Phys. Chem. C 2008, 112 (33), 12669-12676.

NANOSUSPENSIONDefinition:

“A very finely dispersed solid drug particles in an aqueous vehicle in which diameter of suspended particle is less than 1 µm in size, stabilized by surfactants, for either oral and topical use or parentral and pulmonary administration, with reduced particle size, leading to an increased dissolution rate and therefore improved bioavailability”.

Average particle size ranges from 200-600 nm.

In nanosuspension technology, the drug is maintained in the required crystalline state with reduced particle size, Improved bioavailability leading to an increased dissolution rate.

ADVANTAGES Can be applied for the poorly water soluble drugs. Rapid dissolution and tissue targeting can be achieved by IV route of administration. Oral administration of nanosuspensions provide rapid and improved bioavailability. Long-term physical stability due to the presence of stabilizers. Nanosuspensions can be incorporated in tablets, pellets, hydrogels.

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DISADVANTAGES Physical stability, sedimentation and

compaction can causes problems.

It is bulky sufficient care must be taken during

handling and transport.

Uniform and accurate dose cannot be

achieved unless suspension .

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