Lecithin organogels in enhancing skin delivery of drugs

Abstract

Transdermal delivery of drugs has always been a challenge, as stratum corneum (SC, the outermost layer of skin) is not easy to traverse. SC consists of keratinized, flattened remnants of once actively dividing epidermal cells, and its main function is to prevent entry of exogenous substances into the systemic circulation via the skin. Therefore, one option to overcome this problem is to design drugs that have the inherent ability to squeeze through the SC of the skin and reach the target site (systemic circulation) without adversely affecting the skin membrane. In practice, it is not easy to design a drug/prodrug that would have desired characteristics to pass through the skin barrier. The other relatively simpler option includes the use of carrier systems that can help in delivering the drug entity from the SC to the systemic circulation without causing irreversible alterations to the barrier function of the skin. Different types of delivery systems such as microemulsions, liposomes, nanoparticles, patches, and gels have been explored as effective transdermal delivery systems. All of these drug delivery systems are covered in great detail in various chapters of this book. This chapter will cover the preparation, properties, percutaneous enhancement ability, and application of a unique type of micellar gels, i.e., lecithin organogels (LOs).