EMULSIONS AND SUSPENSIONS
Section I. EMULSIONS
At one time emulsions were frequently prepared in the pharmacy. Now, the
emulsions used in medical practice are primarily prepared by pharmaceutical
manufacturers. This area of the subcourse will discuss some important considerations
of emulsions. Should you be required to prepare an emulsion, you should consult a
reference such as Remington's Pharmaceutical Sciences.
a. Definition. An emulsion is a liquid composed of two immiscible liquids (two
substances which will not mix together), such as oil and water, in which one liquid is
dispersed in small globules throughout the other liquid. The world's most naturally
occurring emulsion is milk.
b. Parts of an Emulsion. An emulsion usually consists of two distinct liquids
called phases. One phase consists of tiny globules. The other phase is the liquid
surrounding the globules. The globule phase may be called the inner phase, the
internal phase or the dispersed phase. The surrounding liquid is called the external
phase or the continuous phase. See Figure 4-1, which illustrates the two phases of an
Figure 4-1. Microscopic view of the two phases of an emulsion.