Performance studies of particle acceleration for transdermal drug delivery.

We have proposed a transdermal biolistic method to accelerate a powder formulation of drugs to penetrate human skin for the treatment of a range of diseases. One of the key issues for designing and evaluating transdermal biolistic system is ensuing that the powder drugs are delivered into the skin with a controllable velocity range and spatial distribution. The aerodynamics of supersonic nozzles and performance of the delivery system were initially studied, mainly analytically and experimentally. In this paper, computational fluid dynamics is utilized to characterize two existing prototype devices, in order to further investigate the transient gas and particle dynamics in their supersonic nozzles. To validate the implemented numerical approach, calculated pressure histories, two-dimensional flow structures and particle velocity distributions are made and compared with the reported experimental measurements. The key features of gas dynamics, gas-particle interaction and performance of the prototype transdermal biolistics are discussed and interpreted.