Page 23 - Reference Guide For Foreign Pharmacy Licensing Exam Theory

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22. Suspension and Emulsion

Dosage forms are classified into three major categories:

1. Liquid dosage form
2. Solid dosage form
3. Semi-solid dosage form

From all these major categories, the following dosage forms are very important study-wise for FPGEE.

1. Suspension
2. Emulsion
3. Tablet and capsule

SUSPENSION

It can be used for oral, external or parenteral use.

The ideal suspension consists of small, uniform sized particles of dispersed phase suspended uniformly without
any tendency to settle.

The particle size of suspended particles normally ranges from 0.5 to 5.0 microns.

The sedimentation property of suspension is best described by Stoke’s law:

= 2 2 ( 1− 2)
9 

V = sedimentation rate in cm/sec
r = radius of suspended particles
1 = density of dispersed phase
2 = density of dispersion medium
 = viscosity of continuous phase in poise
2
g = gravitational constant = 980 cm/sec

The formulation of suspension requires the following agents:

a. Suspending agent
b. Flocculating agent
c. Wetting agent
d. Dispersant
e. Preservative

We will discuss all above agents in detail in chapter “Pharmaceutical Additives”.

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