ABSTRACT:
The main intention of writing this review was to include the recent literature and specially focusing area of development in topical preparation and basic concept of topical drug delivery systems. Topical drug delivery has advantages such as applying the drug directly into skin and it also provides prolonged action on the specific site. There are different topical used formulation among the semisolid dosage forms gel formulations are becoming pre-eminent. Gels are colloids that are 99% liquid by mass, which is immobilized by surface tension among it and a macromolecules system of fibres constructed from a less amount of gelatinous substances present. The nature of solvent used categorizes gel into mainly two basic types ie, organogel and hydrogel. This review includes fundamental advantages of gel formulation above other semisolid formulation and also other aspects like limitation, classification, formulation, mechanism involved and factors affecting gel formulation.