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Pastes are semisolid dosage forms that contain one or more drug substances intended for topical application. One class is made from a single-phase aqueous gel (e.g., Carboxymethylcellulose Sodium Paste). The other class, the fatty pastes (e.g., Zinc Oxide Paste), consists of thick, stiff ointments that do not ordinarily flow at body temperature, and therefore serve as protective coatings over the areas to which they are applied.
The fatty pastes appear less greasy and more absorptive than ointments by reason of a high proportion of drug substance(s) having an affinity for water. These pastes tend to absorb serous secretions, and are less penetrating and less macerating than ointments, so that they are preferred for acute lesions that have a tendency towards crusting, vesiculation, or oozing.
A dental paste is intended for adhesion to the mucous membrane for local effect (e.g., Triamcinolone Acetonide Dental Paste). Some paste preparations intended for administration to animals are applied orally. The paste is squeezed into the mouth of the animal, generally at the back of the tongue, or is spread inside the mouth.