Large Volume Jet Injection

Abstract

Jet injection is a drug delivery technique that removes the requirement for a needle by providing the liquid drug with sufficient momentum to penetrate the skin, and deliver itself into the underlying tissue. Currently, only injectors driven through uncontrollable means (compressed springs or gas) are capable of delivering volumes greater than 0.3 mL. Controllably-actuated jet injectors have the advantage of control over the jet speed and, therefore, the depth and volume of delivery into tissue. This thesis presents a novel mechanism, the compound ampoule, which mechanically separates a jet injection into two phases. This mechanism significantly reduces the power and energy required to perform a given injection and, therefore, significantly increases the volume deliverable with a controllable injector. Before a compound ampoule could be successfully implemented, however, an improved understanding of the requirements for large volume jet injection was needed. This involved the development of a highly controllable, large volume, benchtop injector. This device was used to perform injections that were observed with high speed X-ray, and to perform a large volume tissue injection study using samples of post-mortem porcine tissue. These investigations explored the jet speed requirements of large volume injection and the effects of two phase administration. The results demonstrated that 1 mL can be successfully delivered into tissue in two phases, and that a second phase jet speed of at least 100 m/s is required for successful injection. In addition, the results demonstrated that the jet speed required for successful delivery is dependent on the injection volume. Based on what these studies revealed about large volume, two-phase jet injection, a compound ampoule was manufactured. This device demonstrated successful delivery of 1 mL into tissue samples. The success of this compound ampoule injector demonstrates the feasibility of the delivery of 1 mL with a clinically appropriate, voice coil driven jet injection device.