MAJOR CLASSIFICATION OF AN EMULSION: MAJOR CLASSIFICATION OF AN EMULSION

A. According to the mode of dispersion:

1. O/W (Oil in Water):

- Oil is an internal phase

- Water is an external phase

- e,g.yolk, Vanishing cream

2. W/O (Water in oil):

- Water is an Internal Phase.

- Oil is an External Phase.

- e,g. cold cream,

3. Multiple phases emulsion:

- W/O/W

-o/w/o

B. In case of consistency-

a) Liquid emulsion:

- usually o/w type

- used parenterally, orally & externally

b) Semisolid emulsion:

- o/w or w/o type

- usually used for external purposes.

C.In accordance to particle size-

· Coarse emulsion:

globule size greater than 5μm

· Fine emulsion:

below 5μm

· Microemulsion:

< 120nm

don’t refract light

transperant appearance

D. According to our route of administration

a) Emulsion for internal use:

- oral, IV

b) Emulsion for external use:

- liniment & lotion

E. According to HLB value

a) Hydrophilic:

- o/w type

- HLB value of the water phase 9-18

b) Lipophilic:

- w/o type

- HLB value of the oil phase 3-8

DIFFERENCE BETWEEN O/W AND W/O EMULSIONS

O/W	W/O
Here water is as a dispersion medium and oil is the dispersed phase	Here Oil is as a dispersion medium besides water is the dispersed phase
They are non greasy, removable from the skin surface	They are not water removable & greasy in nature.
Used externally to deliver cooling effect e.g. vanishing cream	Used externally to stop evaporation of moisture from the skin surface e.g. Cold cream
Water soluble drugs are actually released more quickly from o/w emulsions	Oil soluble drugs are more quickly released from w/o emulsions
bitter taste of oils can be masked. So these kind of dosage forms are preferred by consumer & manufacturer.	They are preferred for formulations meant for external use like creams.
O/W emulsions give a positive conductivity test .	W/O emulsions do not give a positive conductivity.. TabletGranulations

MAJOR CLASSIFICATION OF AN EMULSION