Page 24 - Reference Guide For Foreign Pharmacy Licensing Exam Theory

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A suspended system can be classified into two major categories:

a. Flocculated suspension
b. Deflocculated suspension

Flocculated Suspension Deflocculated Suspension

The rate of sedimentation is high. The rate of sedimentation is very low.

The particles of the dispersed phase are in The particles of the dispersed phase exist as a
contact with one another and form a network separate entity.
like structure.

The sediment is loosely packed. The sediment forms a hard cake.

The suspension can be easily redispersed by The suspension cannot be easily redispersed.
shaking.

The supernatant liquid of suspension is clear. The supernatant liquid of suspension is cloudy.

The stability of suspension can be evaluated by measuring sediment ratio and rate.

A sedimentation ratio of suspension can be expressed by the following equation:

Sedimentation ratio: Hu / Ho, where;

Hu = The volume of sediment in period of time (t 1)
Ho = The initial volume of sediment at time (t 0)

EMULSION

Emulsion: It is defined as a heterogenous system of two immiscible phases, one of which is water and the other
is oil.

The particle size of an emulsion droplet ranges between 0.1 and 100 microns.

Emulsion is divided into the following categories:

a. O/W emulsion
b. W/O emulsion
c. O/W/O emulsion and W/O/W emulsion
d. Microemulsion
e. Nanoparticle

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