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The suppositories may be moistened with water before insertion to reduce the tendency of the base
to draw water from mucus.
In addition, those suppositories intended for extended shelf-life should have a preservative added,
such as methyl paraben or propyl paraben, or a suitable combination of the two.
To facilitate administration, glycerinated gelatin suppositories should be dipped in water just before
use.

III. Polyethylene glycol base
It is a synthetic material. PEG 400, PEG1500, PEG 4000.

Advantages
❖ The melting point increases with an increase in molecular weight.
❖ Slowly melt and slowly release.
❖ They dissolve in body fluid rather than melt.
❖ Not sticky.
❖ High viscosity.
Disadvantage

❖ Incompatible with bismuth salt, phenol dissolved some plastic and reduced antimicrobial
activity.

❖ PEG that does not contain at least 20% water should be dipped in water just before use
to avoid irritation of the mucous membrane.

❖ This procedure prevents moisture from being drawn from the tissue after insertion and
stinging sensation.

IV Miscellaneous bases
❖ Chemical or physical mixtures of oleaginous and water soluble or water-miscible
materials.
❖ Emulsions, generally of w/o type (i.e. mixing of cocoa butter with emulsifying agents).
❖ Polyoxyl 40 stearate is a mixture of the mono-stearate and di-stearate esters of mixed
polyoxyethylene diols and free glycols.
❖ Soap may be used as a base (i.e. Glycerin suppositories, USP, with soap as the base).

Preparation of suppositories
Suppositories can be extemporaneously prepared by one of three methods:

❖ Hand rolling.
❖ Compression molding.

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