Abstract: 
Topical drug delivery systems are localized drug delivery systems for the treatment of cutaneous disorders in which the drug is delivered via skin. These systems are generally used for treating local skin infection. Many semisolid preparations including ointments, creams and lotions are available for treating skin ailments. Gels also belong to this category. But some of its properties make it more suitable dosage form than the others in this group. Gels are solid, jelly like materials formed from colloidal mixtures. The major property of a pharmaceutical gel is that it has a solid like consistency upon storage but is breakable through sheer force generated via shaking the bottle or squeezing the tube. Another property which makes it popular is that gels are less greasy and can be easily removed from the skin. Moreover, the gels have a better application property and stability in comparison to other topical formulations like creams and ointments which make it more acceptable in the pharmaceutical industry. In this review, a general overview of the gels are described including its chemistry, classes, formulation considerations, method of preparation and evaluation methods.

Keywords: Gel, Gel Delivery System, Topical Drug Delivery System, Inorganic Gel, Organic Gel.