NEEDLELESS HYPODERMIC INJECTION METHODS AND DEVICE

摘要

A needleless injection device (20) includes an initiator valve (144) controlling flow of compressed gas into a reservoir (168). A poppet valve (170) connecting to the reservoir has a gas pressure regulati on end to regulate flow from the initiator valve into the reservoir. A clamp piston (210) is driven forward by gas pressure from the reservoir and causes jaws (236) to clamp onto a plunger (362) extending into an ampule (360). The poppet valve opens when reservoir pressure reaches the cracking pressure of the poppet valve. Gas from the reservoir rushes through the poppet valve into a drive chamber and forces a drive piston (212), containing the clamp piston and jaws, forward causing the plunger to slide into the ampule. A jet of injectant is ejected out of the nozzle of the ampule and penetrates through the patient's skin. An improved method of needleless injection uses a specific pressure profile, ampule nozzle diameter, patient, injection site, and injectant parameters.