A Comprehensive Review on Transdermal Drug Delivery System

Abstract

Transdermal Drug Delivery Systems (TDDS) provide a non-invasive and patient-friendly method for delivering drugs directly into systemic circulation through the skin. They offer significant advantages over oral administration by bypassing first-pass metabolism, reducing gastrointestinal irritation, and improving adherence through sustained and controlled drug release. Successful transdermal delivery depends on the skin’s structure, the physicochemical properties of the drug, and physiological factors such as skin hydration, temperature, and integrity. Drug permeation occurs through transepidermal (transcellular and intercellular) and transappendageal routes, but is mainly limited by the barrier function of the stratum corneum. To overcome this resistance, various chemical, biological, physical, and natural permeation enhancers are incorporated. TDDS are widely applied in pain management, hormone therapy, cardiovascular treatment, smoking cessation, and neurological disorders, and they continue to expand into areas like vaccination and dermatological care. Advances in microneedles, iontophoresis, and nanoformulations further enhance their therapeutic potential.

Keywords: Transdermal drug delivery, Skin permeation, Stratum corneum barrier, Permeation enhancers, Microneedles, Controlled release systems, physicochemical properties, Transappendageal pathway, Nanoformulation technology.