Transdermal drug delivery by microneedles: does skin metabolism matter?

Microneedle arrays have been shown to increase skin permeability for the transdermal delivery of drugs with high molecular weights. Various theoretical studies have been proposed to predict the drug transport behaviour after drug injection using microneedles. However it is important for the optimal design of microneedle systems to consider the effects of biological factors such as skin metabolism and variations in pharmacokinetic parameters as well as to improve the enhancement of skin permeability. A mathematical model for microneedle systems is introduced and applied to simulate the verapamil transport with metabolism in the skin. A comparative analysis for a transdermal delivery of verapamil from microneedles is presented in this paper. The results indicate that the skin metabolism does not markedly affect the skin permeation after verapamil injection using microneedles.