Year: 2003
Type: dissertation
Abstract: A needle-less injection device is capable of delivering a liquid drug through skin tissue via a high-speed stream.Devices currently on the market use compressed gas to provide the necessary drug pressure.Shape memory alloy, due to its ability to generate high stresses and its contractile properties, has recently been proposed as a method of actuation for a needle-less injection system.A proof of concept model described here injects, with marginal success, into pig skin tissue to depths of 2 mm and at volumes of up to 200 pL.The diameter of the fluid stream was 150 yIm.This device uses six 380 pIm NiTi wires around the 150 mm long central body to contract a 6 mm piston a distance of 7 mm.Contraction of the NiTi wires was done by joule heating from current supplied by a 50 V 0.156 F capacitor bank.Further injection tests were conducting with a second prototype having eight NiTi wires on the body and a variable drug volume.Measurements of energy dissipation, piston position, drug injection speed and injection success were conducted using several interchangeable modules.Drug vials ranged in volume from 20 yL to 500 pL with an orifice size of 100 ym.It was found that injections of 20 yIL penetrated the tissue to depths of 10 mm while volumes of 250 /L only penetrated 1 mm and 500 ItL drug vials had no injection success.Measured drug speeds for the 20 pL and 250 1tL volumes reached 160 m/s and 65 m/s respectively.Energy dissipation during typical successful 15 ms injections was approximately 60 J. Tests from the second prototype show that drug vial diameters from 3mm to 5 mm have the most promise for successful injections.
Author: Robert J. Dyer
Language: English
Subfield: Pharmaceutical Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1530533082