Experiments and Modeling of Air-Powered Needle-Free Liquid Injectors

Abstract

Liquid jet injectors are biomedical devices used for drug delivery without the use of hypodermic needles. These devices generate a high-speed small-diameter liquid jet of sufficient pressure to penetrate the skin and deliver an appropriate amount of medication. In this study, a detailed investigation on needle-free liquid injection systems powered by compressed air is carried out.Experiments are conducted using a custom-built experimental prototype which makes it possible to vary a number of parameters. The experimental results are used to validate a fluid mechanics model for air-powered needle-free injectors. The model, based on the work of Baker and Sanders

Current engineering and clinical aspects of needle-free injectors: A review

“…The force required for driving the piston could be generated by an expanding gas (usually CO 2 or N 2 ) or air [15][16][17][18], the energy from the sudden release of a compressed spring [19][20][21], the Lorentz actuators [22][23][24] or piezoelectric actuators [25][26][27]. The Lorentz and piezoelectric actuators could provide electronic control over the injection speed.…”

“…Expanding gas or air is commonly used as the operating force in many commercially available NFJIs [4,15,17] possibly because compressed gas can provide a higher energy density, improved flexibility and could deliver larger volumes of drugs. In these devices, an expanding gas accelerates the firing piston or ram, which in turn energizes the fluid to be injected by creating a high-pressure pulse.…”

“…[44]). 15,16,[45][46][47]. Stand-off distance can be defined as the distance from the nozzle exit to the skin surface, and it is a parameter that could be omitted from the performance evaluation of an NFJI.…”

“…However, in pursuit of a single factor that could accommodate these factors, many researchers employ different approaches. Apart from the microjet velocity, jet power [24,39] and stagnation pressure [15,16] of the jet at the skin surface were reported as the quantifiers.…”

“…Several studies have shown that a vaccine delivered using Stagnation pressure [15][16][17] and penetration depth (gelatin [18], cadaver [44])…”