Definition of emulsion Emulsion is a liquid preparation containing two immiscible liquid (oil and water) one of which is uniformly distributed through out the other by the addition of an emulsifying agent. Emulsion is a liquid preparation containing two immiscible liquid (oil and water) one of which is uniformly distributed through out the other by the addition of an emulsifying agent. The emulsifying agent ensures that the oil phase is finely dispersed throughout the water as minute particles. The emulsifying agent ensures that the oil phase is finely dispersed throughout the water as minute particles.

Micro emulsions Micro emulsions Clear dispersion of o/w or w/o is called micro emulsions Clear dispersion of o/w or w/o is called micro emulsions They appear homogeneous to the naked eye They appear homogeneous to the naked eye Also called solubilized system because macroscopically they behave as true solutions Also called solubilized system because macroscopically they behave as true solutions Becoming more popular due to clear preparation Becoming more popular due to clear preparation Free of stability problems Free of stability problems

Emulsifying agents Emulsifying agents Emulsifying agents for internal use Emulsifying agents for internal use Acacia,Tragacanth,methyl cellulose,wool alcohols, wool fat Acacia,Tragacanth,methyl cellulose,wool alcohols, wool fat Emulsifying agents for external use Emulsifying agents for external use Emulsifying waxes Emulsifying waxes Cetomacrogol,Cetrimide Cetomacrogol,Cetrimide

Classification- Emulsifying agents Natural- vegetable sources Natural- vegetable sources Acacia,tragacanth,agar,starch Acacia,tragacanth,agar,starch Natural- animal sources Natural- animal sources Gelatin, egg yolk, wool fat Gelatin, egg yolk, wool fat Semi-synthetic poly saccharides Semi-synthetic poly saccharides Methyl cellulose, Sod.carboxy methyl cellulose Methyl cellulose, Sod.carboxy methyl cellulose

Classification contd. Synthetic Synthetic Anionic- sodium lauryl sulphate,dioctyl sodium sulphosuccinate Anionic- sodium lauryl sulphate,dioctyl sodium sulphosuccinate Cationic- benzalkonium chloride, cetrimide Cationic- benzalkonium chloride, cetrimide Non- ionic- glyceryl monostearate Non- ionic- glyceryl monostearate Inorganic emulsifying agents Inorganic emulsifying agents Milk of magnesia,meg.oxide,bentonite Milk of magnesia,meg.oxide,bentonite

Classification contd. Saponins Saponins Alcohols Alcohols Cholesterol,carbowaxes,lecthins Cholesterol,carbowaxes,lecthins

Advantages of emulsions Advantages of emulsions Unpalatable drugs can be administered in palatable form Unpalatable drugs can be administered in palatable form Unpalatable oil-soluble drugs can be administered in palatable form Unpalatable oil-soluble drugs can be administered in palatable form Aqueous phase can be easily flavoured Aqueous phase can be easily flavoured Oily sensation easily removed Oily sensation easily removed Increased rate of absorption Increased rate of absorption Possible to include two incompatible ingredients, one in each phase of the emulsion Possible to include two incompatible ingredients, one in each phase of the emulsion

Disadvantages of emulsions Preparation need to be shaken well before use Preparation need to be shaken well before use Measuring device needed for administration Measuring device needed for administration Need technical accuracy for measuring doses Need technical accuracy for measuring doses Storage conditions may affect stability Storage conditions may affect stability Bulky, difficult to transport, prone for container breakage Bulky, difficult to transport, prone for container breakage Liable to microbial contamination which can lead to cracking. Liable to microbial contamination which can lead to cracking.

Classification of emulsions Emulsions are of two types Emulsions are of two types Oil in water type(o/w) Oil in water type(o/w) Water in oil type(w/o) Water in oil type(w/o) O/W type O/W type Oil phase is finely dispersed throughout water Oil phase is finely dispersed throughout water as minute granules- as minute granules- Oil -Dispersion phase, Water-Dispersed phase Oil -Dispersion phase, Water-Dispersed phase Eg..Gentamycin sulphate,acyclovir Eg..Gentamycin sulphate,acyclovir

Water in oil type-W/O Water in oil type-W/O Aqueous phase is finely dispersed throughout the oil phase. W/O Aqueous phase is finely dispersed throughout the oil phase. W/O Water/aqueous-Dispersion phase, Oil-Dispersed phase Water/aqueous-Dispersion phase, Oil-Dispersed phase Eg: Hydroxyzine inj (atarax) Eg: Hydroxyzine inj (atarax)

Classification –Therapeutic importance Oral emulsions Oral emulsions liquid paraffin, cod-liver -oil liquid paraffin, cod-liver -oil Parenteral emulsions Parenteral emulsions Diclofenac sod.i/m,Robitussin,MUVIT Diclofenac sod.i/m,Robitussin,MUVIT Topical emulsions Topical emulsions Creams like Histergan,clovir Creams like Histergan,clovir

Preparation of emulsions Preparation of emulsions Primary emulsion-Prepare a concentrate Primary emulsion-Prepare a concentrate Dilution of the concentrate Dilution of the concentrate Preparation of primary emulsion Preparation of primary emulsion 1. Measure the oil accurately in a dry measuring cylinder and transfer to a dry porcelain mortar allowing all the oil to drain out. 2. Measure the quantity of the aqueous vehicle required for the primary emulsion and keep aside. 3. Weigh the emulsifying agent and place on the oil in the mortar. Mix lightly with the pestle, just sufficient to disperse any lumps (over mixing will result in poor quality)

Prepn. Contd. Add all the required vehicle in one addition and mix vigorously using a pestle with a shearing action in one direction Add all the required vehicle in one addition and mix vigorously using a pestle with a shearing action in one direction When the product becomes white and produces a clicking sound the primary emulsion has formed.The product should be a thick white cream. When the product becomes white and produces a clicking sound the primary emulsion has formed.The product should be a thick white cream.

Dilution of primary emulsion Dilute the primary emulsion drop by drop with very small quantities of the remaining aqueous vehicle. Mix carefully in one direction with the pestle. Dilute the primary emulsion drop by drop with very small quantities of the remaining aqueous vehicle. Mix carefully in one direction with the pestle. Transfer emulsion to a measuring cylinder with rinsings.Add other liquid ingredients if necessary and make up the final volume Transfer emulsion to a measuring cylinder with rinsings.Add other liquid ingredients if necessary and make up the final volume

Test for the type of emulsion Test for the type of emulsion On shaking oil and water both phases form droplets. The phase that persists in droplets for longer time should become the dispersed phase. This will be surrounded by the continuous phase. On shaking oil and water both phases form droplets. The phase that persists in droplets for longer time should become the dispersed phase. This will be surrounded by the continuous phase. If oil droplets persists- O/W emulsion If oil droplets persists- O/W emulsion If water droplets persists- W/O emulsion If water droplets persists- W/O emulsion