Unlocking the Skin Barrier Limitation Through Adaptive Polymer–permeation Enhancer Combinations in Transdermal Drug Delivery

The skin offers a convenient way to get a drug into the bloodstream, and transdermal drug delivery systems (TDDS) are built to use it. The drug is delivered slowly and steadily from a patch adhered to the skin resulting in a therapeutically effective plasma concentration of drug for many hours or days. The difficulty is the skin itself. The stratum corneum keeps most molecules out, so only a limited group of drugs can be delivered through it. The efficiency of a transdermal delivery system relies on a number of factors including drug properties, skin conditions, formulation design and the choice of permeation enhancer. Therefore, new methods are being developed using microneedles, nanocarriers, iontophoresis, sonophoresis, electroporation and new polymers to increase the variety of drugs that can be delivered. This review offers an overview of TDDS, covering its principles, types, advantages, limitations, evaluation methods, and recent technological developments. On the whole, TDDS stands out as a promising and patient-friendly approach to modern drug delivery, holding considerable potential for future pharmaceutical applications and better therapeutic outcomes.