Neoteric Direct Physical Approaches in TDDS: A Boon for Permeation Enhancement

Human skin has been explored for decades as a potential route for the delivery of various substances. It has shown considerable promise for the delivery of medications into the systemic circulation. It is also beneficial to treat local skin symptoms through the skin itself. However, the rigid stratum corneum layer has served as the biggest barrier to transdermal drug delivery. Various methods have been designed to overcome the barrier of the stratum corneum layer to allow the molecule to pass through it. These methods have been broadly classified into chemical and physical approaches. This study is an overall review of the physical approaches being used in transdermal drug delivery for overcoming the stratum corneum layer. Physical approaches also include direct and indirect methods; we will be considering the direct approaches herein.