Learning Objectives

• Introduction to semisolids
• Mechanism of drug absorption
• Permeation enhancers and kinetics of drug absorption

Semisolid dosage forms are mainly meant for external application on the skin or mucous membrane. They are traditionally used for treating topical ailments. They are also used for treating ophthalmic, nasal, buccal, rectal and vaginal ailments. Semisolid dosage forms may be used for therapeutic, cosmetic or protective properties. Examples are ointments, pastes, creams, gels and jellies. Suppositories are also included in this category, although they come under solid unit dosage forms.