Pharmaceutical Pastes are semisolid dosage forms that contain one or more drug substances intended for topical/external application to the skin. They are generally very thick & stiff. They differ from ointments in their consistency, as they contain larger amounts of finely dispersed solids (20% to 50%) and so they are thicker and stiffer.
Ointments are semisolid preparations intended for external application to the skin or mucous membranes for protection (calamine, ZnO, TiO2, Silicones) or emollient effect.
| Paste | Ointment |
|---|---|
| Contains a large amount of finely powdered solids such as zinc oxide, calcium carbonate, starch etc | contains medicaments which are dissolved/suspended/emulsified in the base |
| very thick and stiff so they do not spread easily, result into localizing drug delivery | soft semisolid |
| less greasy | more greasy |
| applied with a spatula or spread on lint | applied on the skin |
| form a protective coating to area where it s applied | used as a protective or emollient for the skin |
| Paste contains a large amount of finely powder which is porous in nature, hence perspiration can escape | used for protection of lesions |
| they are less macerating than ointments | they are more macerating in action |