EMULSIONS

Definition:

An emulsion is a system of two immiscible phases, one of which is dispersed as fine globules throughout the other.

Emulsions may also be defined as a thermodynamically unstable system of at least two immiscible liquid phases, one of which is dispersed as globules in other liquid phase, stabilized by presence of emulsifying agent.

The liquid phase that is subdivided is termed the dispersed phase and the other liquid surrounding the globules is the continuous phase.

Emulsion is stabilized by adding emulsifying agent.

Dispersed phase or continuous phase may consist of mobile liquids or semisolids, so emulsified systems include lotions, creams ointments.

Particle of globules size may generally extend from about 0.1 to 10 micron.

DEFINITION OF pH

Definition of pH:

pH is defined as the negative log of the hydrogen ion concentration, or pH = -log [H+]. pH may be an abbreviation of power of hydrogen or more explicitly the power of hydrogen ion concentration The pH scale commonly ranges from 0 to 14, which denotes a measure of the alkalinity or acidity of a solution. The pH scale is equal to 7 numerically for the neutral value of pH. An increase in the numerical value above 7 denotes an increase in alkalinity, while a decrease in the value below 7 shows an increase in the acidity of the solution.