Recent Methods to Enhance Drug Permeation in Transdermal Drug Delivery Systems

Abstract

Transdermal drug delivery systems are poised as an alternative to traditional drug delivery systems like oral and parenteral routes. The main advantages of transdermal drug delivery systems are low first pass metabolism, drug administration for long period of times, improved patient compliance and are generally less expensive. Despite several advantages of transdermal drug delivery systems over traditional routes only a handful of drugs are available as transdermal patches because only very few drugs are suitable for transdermal patches. The factors that limit the formulation of drugs as transdermal patches are high molecular weight, hydrophilicity, solubility, blood flow, age of the patient etc. However, to overcome the above limitations and increase the number of drugs that can be formulated as transdermal patches several methods that enhance the permeation of drugs has been discovered. The recent techniques that are employed to enhance the permeation of drugs via transdermal patches are sonophoresis, iontophoresis, and electroporation and micro needles. These techniques enhance the permeation by causing reversible disruption of startum corneum of the skin without affecting the underlying tissues and by providing a driving force for transport of drugs across the membrane.