A REVIEW ARTICLE ON TRANSDERMAL PATCHES: A COMPREHENSIVE GUIDE

Transdermal drug delivery systems (TDDS) are non-invasive and provide an alternative route to the traditional method of drug administration. Drugs pass through the skin and into the bloodstream through these systems, which confer advantages such as continuous drug delivery, avoidance of first-pass metabolism, and bypassing the digestive system. History The history of TDDS begins as early as the early 20th century, and great developments have been made over the years, especially during the 1960s and 1970s. In 1979, the first FDA approved transdermal patch came out, and since then, different types of TDDS have emerged, such as single-layer drug-in-adhesive patches, multi-layer drug-in-adhesive patches, reservoir patches, matrix patches, and microneedle-based patches. TDDS designing and development are done in accordance with several factors, like drug selection, type of patch, and evaluation parameters. The evaluation parameters include thickness, weight uniformity, folding endurance, percentage moisture content, content uniformity test, moisture uptake, flatness, tensile strength, and skin permeation. In-vitro methods, such as diffusion cell permeation tests, are used to evaluate the release of drugs from TDDS. In-vivo studies, including animal models and human clinical trials, are also conducted to assess the performance of TDDS. The advantages of TDDS include continuous drug delivery, avoidance of first-pass metabolism, and bypassing the digestive system. Challenges associated with TDDS are skin irritation, inconsistent absorption, and limited dosing options. TDDS provides an alternative promising route for the administration of drugs in contrast to traditional methods of drug administration. Ongoing research and development are focused on improving the design, efficacy, and safety of these systems.