FORMULATION AND EVALUATION OF EMULGEL FOR TOPICAL DRUG DELIVERY

Topical drug delivery systems offer a convenient and effective mode of delivery of drugs to the skin surface, which increases local concentration of the drug while minimizing systemic adverse effects. Emulgels are considered as one of the potential dosage forms, which offer solution for topical drug delivery. They are mixtures of an emulsion and gel matrix and allow delivery of both hydrophilic and hydrophobic drugs. This article highlights a discussion on topical drug delivery and emulgels, including their types, formulating ingredients, methods of preparation, and evaluation parameters. A brief description on the anatomy of the skin and its barrier properties towards topical drug delivery is also presented. Emulgels are described with a focus on the aqueous and oily phases, emulsifying agents, permeation enhancers, and gelling agents. The physiological, physicochemical, and formulation factors that may influence topical drug absorption are also outlined. Moreover, the article discusses the various types of emulgels: macroemulgels, microemulgels, and nanoemulgels, and their characteristics such as particle size and stability. Other evaluation parameters include physical appearance, pH, viscosity, stability, irritation, and zeta potential, particle size distribution, polydispersity index, swelling index, drug content, spreadability, and extrudability. Emulgels can be used as a versatile topically applicable dosage form due to their enhanced spreading ability, patient acceptability, high drug loading, stability, and controlled release property. Future work focused on the evaluation and formulation of emulgels would be of paramount importance in topical and transdermal drug delivery.