Details for Patent: 7,942,846

Title:	Needleless syringe using supersonic gas flow for particle delivery
Abstract:	A needleless syringe having a membrane (28) which is ruptured by gas pressure to generate a supersonic gas flow in which particles containing a therapeutic agent are injected.
Inventor(s):	Bellhouse; Brian John (Islip, GB), Sarphie; David F. (Oxford, GB), Greenford; John Christopher (Abingdon, GB)
Assignee:	Powderject Research Limited (Oxford, GB)
Filing Date:	Aug 31, 2007
Application Number:	11/848,432
Claims:	1. A needleless syringe comprising: an energizing mechanism to provide a gaseous pressure; a particle cassette for holding particles to be injected; a nozzle configured to accelerate said particles; a silencer, downstream of said nozzle, for attenuating gas discharge noise; such that, upon activation of said needleless syringe, said particles are entrained in a gas flow, accelerated in said nozzle, and delivered to a target. 2. The needleless syringe of claim 1, wherein said nozzle is a convergent/divergent nozzle. 3. The needleless syringe of claim 1, wherein said silencer also serves, in use, to space a downstream end of the nozzle from a target. 4. The needleless syringe of claim 3, wherein the spacing is up to 35 mm. 5. The needleless syringe of claim 1, wherein said silencer provides a tortuous path from a downstream end of the nozzle to at least one outlet to the atmosphere. 6. The needleless syringe of claim 1, wherein said silencer comprises a sound attenuating medium. 7. The needleless syringe of claim 1, wherein said particle cassette comprises particles to be injected located between two rupturable membranes. 8. The needleless syringe of claim 1, wherein said particle cassette, nozzle and silencer are made of plastics material.