Learning Objectives

• Introduction to pastes
• Differences between ointments and pastes

Pastes can be defined as the semisolid dosage forms mainly meant only for external application to the skin. They are usually stiffer in nature but are less greasy than ointments. They do not melt at ordinary temperature and hence acts as a protective layer over the skin surface.

Bases Used for Paste Preparation

Hydrocarbon or oleoginous bases, water-miscible bases and water-soluble bases are used for the preparation of pastes.

Method of Preparation

Pastes are prepared either by trituration or by fusion method.

Differences between Ointments and Pastes

Table 7.3 provides the differences between ointments and pastes.

 

Table 7.3 Differences between Ointments and Pastes

Ointment	Paste
1. It contains less concentration of solids.	It is more concentrated than ointments.
2. It is less viscous in nature.	It is more viscous in nature.
3. It is less stiff in nature.	It is more stiff in nature.
4. It is more greasy in nature.	It is less greasy in nature.
5. It can be applied to both skin and mucous membrane.	It can be applied only to the skin surface.
6. Oleoginous, water-soluble, water-miscible, and absorption bases can be used for preparation.	Except absorption bases, all other bases can be used.
7. It can be prepared by fusion, trituration, spatulation, and chemical reaction methods.	It can be prepared by fusion and trituration methods.