Ointment

An ointment is a viscous semisolid preparation used topically on a variety of body surfaces. These include the skin and the mucus membranes of the eye (an eye ointment), vagina, anus, glans and nose. An ointment may or may not be medicated.

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The vehicle of an ointment is known as ointment base. The choice of a base depends upon the clinical indication for the ointment, and the different types of ointment bases are:

1. Hydrocarbon bases. e.g. hard paraffin, soft paraffin.
2. Absorption bases. e.g. wool fat, beewax.
3. Water soluble bases. e.g. macrogols 200,300,400.

Properties which affect choice of an ointment base are:

1. Stability
2. Penetrability
3. Solvent property
4. Irritant effects
5. Ease of application and removal

Methods of preparation of ointments

Trituration: In this finely subdivided insoluble medicaments are evenly distributed by grinding with a small amount of the base followed by dilution with gradually increasing amounts of the base.

Fusion: In this method the ingredients are melted together in descending order of their melting points and stirred to ensure homogenity

Related topical preparations include creams, lotions, liniments and gels.