A review on transdermal drug delivery system

Drugs that are applied topically are delivered using transdermal drug delivery devices. These are pharmaceutical preparations of varying sizes, containing one or more active ingredients, intended to be applied to the unbroken skin in order to deliver the active ingredient after passing through the skin barriers, and these avoid first pass metabolism. Today about 74% of drugs are taken orally and are not found effective as desired. To improve efficacy transdermal drug delivery system was emerged. A notable advantage of transdermal drug delivery compared to other methods like oral, topical, intravenous (IV), and intramuscular (IM) administration is its controlled release of medication into the patient's system. This controlled release is achieved either by using a porous membrane enclosing a medication reservoir or by utilizing the patient's body heat to melt thin layers of medication embedded in the adhesive. Despite its benefits, transdermal drug delivery has certain limitations due to the skin's effective barrier function. Only molecules with small sizes can efficiently permeate the skin and consequently be delivered through this method.