MULTIPLE EMULSION & SUBMICRON EMULSION

Jony Mallik M.Pharm

CONTENT 1) Definitio of Emulsion.

2) What is multiple emulsion?

3) What is emulsifing agent?

4) Mechanism of drug release.

5) Equipments used in emulsion preparation.

6) Application 7) What is Microemulsion?

8) Characteristics of microemulsion.

9) Advantage , Disadvantage & Application of microemulsion.

EMULSION



DEFINATION

:”emulsion is a

thermodynamically unstable immiscible liquids.

” mixture of two 

TYPES:

O/W W/O/W =water phase =oil phase Micro(transperent) W/0 O/W/O

 Multiple emulsion are complex system which consist of both w/o and o/w at the same time.

 There are potential matrices for the encapsulation of biactive compounds and for the controlled release compounds  w/o/w multiple emulsion are system where small water droplets are entrapped within larger oil droplets and they are disperse continous water phase  Because of presense of reseroir phase that can be use to prolong release of active ingredients.

 Multiple emulsion w/o/w contain two emulsifiers: 1 Low HLB surfactant (Hydrophobic in nature) 2 High HLB surfactant (Hydrophilic in nature)  Low HLB surfactant use in disperse phase  High HLB surfactant use in continous phase.

MULTIPLE EMULSION

W/O/W SYSTEM HYDROPHILIC SURFACTANT HYDROPHOBIC SURFACTANT O/W/O SYSTEM =water phase =oil phase

surfactants Anionic



Sodium oleate



Pottasium oleate



Glyceryl monostearate cationic



Benzalkonium chloride Non ionic



span 80



span20



Tween 20



Tween 60



Tween 80

Mechanism of release of drug:  Two type inter phase in w/o/w multiple emulsion 1 Primary interface lying between the inner w/o phase contains the low HLB surfactant.

2 Secondary interface lying between droplets and continuous aqueous phase. Low and high HLB surfactant present in it. When hydrophilic surfactant in the continuous aqueous phase exceed its critical micelle concentration the resultant micelles may solubilize the hydrophobic surfactant present in oil phase.

 Resulting in a decrease in the hydrophobic surfactant concentration and rupture the oil layer and lose of internal aqueous phase.

METHOD OF PREPARATION 1) Solvent evaporation method 2) Two step emulsification.

3) Phase inversion technique.

SOLVENT EVAPORATION TECHNIQUE

EQUIPMENTS shaft To electric motor Impeller/blade Mechanical stirrer



MECHANICAL STIRRES

• Impellers mounted on shaft.

•

Paddles or blade

•

Degree of

is used.

agitation

a is controlled by speed

liquid flow pattern

but is by type of impellers.

inlet Vibrating blade outlet Nozzle jet ultrasonifiers



ULTRASONIFIERS

•

Use

ultrasonic enegry

for emulsification.

inlet homogenizer



HOMOGENIZR outlet

• Forcing liquid mixture through

small orifice at very high pressure.

(500 to 5000psi)

spring Small orifice

• Yiled emulsion of very

low particle size

(1nm).

APPLICATION • In theory, multiple emulsions have significant potential for breakthrough applications in food, agricultural, pharmaceutical, nutraceutical, and cosmetic industries in which they can facilitate the sustained release and transport of active material.

• In cosmetics, these systems can prevent degradation of an active ingredient and release it at a controlled rate.

• They can also improve dissolutions or solubilization of insoluble materials.

• Due to these properties, multiple emulsions find applications related to protecting sensitive and active molecules such as vitamins C and E from the external phase—a process called antioxidation.

Microemulsions

Microemulsions are

thermodynamically stable

,

optically transparent

, isotropic dispersions of aqueous and hydrocarbon liquids stabilized by an interfacial film of surfactant molecules Microemulsions are monodispersed spherical droplets (

diameter < 100 nm

) of water in oil or oil in water, depending on the nature of the surfactant.

Microemulsions and (Macro) emulsions are Different Microemulsion

Thermodynamically Stable Droplet size 10 - 100 nm (transparent) High surface area: 200 m 2 /g Ultra Low O/W IFT (10 -2 – 10 -3 mN/m) W/O , O/W and Bicontinuous types

Macroemulsion

Kinetically Stable 1-10  m (opaque) Low surface area: 15 m 2 /g O/W IFT 1-10 mN/m W/O or O/W types

MODERN EQUIPMENTS Bitumen-emulsion system UVB-14 Inline homogenizer

Vacuume emulsifier

Vacuume emulsifier for Eye ointment and creams. Intake homogenizer