Rohit Tiwari, Manish Jaimini, Shailender Mohan, Sanjay Sharma

Transdermal drug delivery has made an important contribution to medical practice, but it has yet to fully achieve its potential as an alternative to the oral delivery and hypodermic injections. An advantage of a transdermal drug delivery route over other types of delivery systems such as oral, topical, intravenous, intramuscular, etc. is that the patch may essentially can provide a controlled release of the medication into the patient, usually through either a porous membrane covering a reservoir of medication or through body heat melting thin layers of medication embedded in the adhesive. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine.
Keywords: Transdermal Drug Delivery, Skin Permeation, Membrane moderated systems, Adhesive diffusion controlled system, Microreservoir system.