Experimental studies on shock wave and particle dynamics in a needle-free drug delivery device

Abstract Recently a needle-free drug delivery device as an innovative injection device has been widely used in medical fields. Drug powders induced with the high momentum by a moving shock wave can be directly delivered into skin layers. The main component of this device is a contoured shock tube, which consists of a micro shock tube and an expanded nozzle. Drug powders and gas flows are induced by a moving shock wave generated in the micro shock tube and accelerated in the expanded nozzle. The most difficult operation is that the momentum of drug powders should be strictly controlled. In present experimental studies, a micro shock tube was designed to investigate the shock wave propagation. A sonic or a supersonic nozzle installed at the exit of the micro shock tube was studied to observe the particle acceleration. Different diaphragms for initializing incident shock waves were investigated as well. Particle tracking velocimetry (PTV) measurement was carried out to investigate the motion of solid particles. In order to visualize the shock wave propagation, Schlieren visualization method was also carried out. The primary incident shock wave and the reflected shock wave induced by the closed end of the driven section were clearly observed.