Liposomes as a topical drug delivery system

Abstract

In the past decade, liposomal formulations have been extensively employed to enhance the efficiency of drug delivery via several routes of administration. In a number of instances, liposomal drug formulations have been shown to be markedly superior to conventional dosage forms, especially for intravenous and topical modes of administration of drugs. The major advantages of topical liposomal drug formulations accrue from their demonstrated ability: (i) to reduce serious side effects and incompatibilities that may arise from undesirably high systemic absorption of drug; (ii) to enhance significantly the accumulation of drug at the site of administration as a result of the high substantivity of liposomes with biological membranes; and (iii) to readily incorporate a wide variety of hydrophilic and hydrophobic drugs. Liposomes are also non-toxic, biodegradable and are readily prepared on a large scale. This paper presents a review of topically applied liposomal formulations with emphasis on the evaluation of liposomal systems in a wide variety of animal models and human skin using both in-vivo and in-vitro techniques. The mechanism by which liposomes facilitate deposition of drugs into the skin and potential applications of topically applied liposomes are discussed.