Loading effects on the performance of needle free jet injections in different skin models

Abstract

Intradermal delivery of vaccines with jet injection is one of the leading alternatives to conventional delivery with hypodermic needles via the Mantoux technique. However, for a given fluid, the effects of various parameters related to injector design, as well as skin properties are still not well understood. Whilst the key design parameters are orifice diameter, jet speed, ampoule volume, and standoff distances, we must also consider applied load of the device on the skin, and axial skin tension. These parameters are all studied herein using different ex-vivo models (guinea pig, pig and human skin) and different fluid viscosities. We find that the applied load can have a significant effect on the amount of drug delivered through the skin, as well as the fluid dispersion pattern in the intradermal tissues. Regardless of skin type or fluid viscosity, we show that minimal standoff and applied loads of approximately 1 kg should be used to maximize injection efficiency when targeting intradermal tissue.