(160w) Optimizing Needle-Free Jet Injections for Intradermal Delivery

Needle-free jet injectors leverage the high speed of a liquid jet with the micro-scale size of a mosquito’s proboscis to puncture the skin to deliver a therapeutic drug. The actuation mechanism of such devices has been based on compressed gas, spring-power, laser-induced thermal breakdown, and Lorentz coils, whereby the actuation force can be tuned to deliver the drug into different target regions (intradermal and intramuscular). Needle-free methods are attractive for many reasons, but the advent of DNA vaccines has fueled interest in optimizing the performance of jet injectors due to higher immunogenicity. Although these devices have myriad advantages over conventional syringe injections in targeted transdermal drug delivery, there are factors limiting their widespread acceptance in the community – namely – inefficient delivery, pain, bruising, and inconsistent depth of delivery. Here, we present our work on optimizing the design parameters associated with jet injectors to maximize delivery efficiency and consistency. We used porcine skin, guinea pig skin and human skin in this study as skin models. In addition to jet speed, orifice exit diameter of nozzle, physical properties of injectate, target volume of injectate to be delivered, skin properties, stand-off distance, and loading of nozzle are some of the parameters which were studied to understand their effect on the dispersion of drug inside skin and the percentage delivery inside skin.