Microplasma Drug Delivery

Abstract

There are several techniques to perform drug delivery. One of the newest methods of drug delivery through the skin is the application of plasma. Reactive species generated by plasma can change the chemical composition of the skin, change the structure and extract lipids of the lipid barrier, create pores in or etch the surface of the skin. These changes have an influence on the barrier function of the skin which can be decreased. The main barrier of the skin is called stratum corneum. The structure and composition of the stratum corneum and function of the components is described. Possible interaction of plasma particles with skin is presented and compared with interaction of plasma species with carbon or hydrocarbon surfaces. Active species which can effectively interact with lipid molecules is introduced. Hydrophilic drugs and drugs with high molecular weight can penetrate very difficult through the skin or cannot penetrate the skin at all. As a model, a drug, Cyclosporine A, was studied. Cyclosporine A is a lipophilic drug with a molecular weight of 1203 Da which is used during and after organ transplantation to prevent rejection. The Hairless Yucatan micropig was used to simulate human skin. A film electrode was used to generate plasma that was used for skin treatment. An AC voltage (V 0-p = 0.6-1.5 kV, 25 kHz) was applied with flowing gas (5 L/min). The barrier function of the skin was evaluated by a Franz cell experiment and high performance liquid chromatography (HPLC) for a particular drug. An effective amount of drug in human body was determined by pharmacokinetic model.