Claims for Patent: 5,899,880

Summary for Patent: 5,899,880

Title:	Needleless syringe using supersonic gas flow for particle delivery
Abstract:	A needleless syringe having a membrane 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 J. (Islip, GB), Sarphie; David F. (Oxford, GB), Greenford; John C. (Abingdon, GB)
Assignee:	Powderject Research Limited (Oxford, GB)
Application Number:	08/483,734
Patent Claims:	1. A needleless syringe for delivering particles having a nominal particle size of at least about 10 .mu.m, said syringe comprising: an elongate tubular nozzle having upstream and downstream ends, and a divergent downstream section; means for positioning a source of particles at the upstream end of the tubular nozzle; and energizing means for releasing compressed gas through a source of particles positioned at the upstream end of the nozzle and into the nozzle to produce within the nozzle a gas flow with particles entrained therein, wherein said gas flow is capable of delivering said particles to a target surface at a velocity of 200 m/sec or greater. 2. The syringe of claim 1 further comprising a reservoir of compressed gas arranged upstream from the nozzle and communicating with the upstream end of said nozzle. 3. The syringe of claim 1, wherein the energizing means comprises a chamber arranged above the upstream end of the nozzle, said chamber having an upstream end, and a downstream end which communicates with the upstream end of the nozzle. 4. The syringe of claim 3, wherein the energizing means further comprises means for effecting a controlled build up of gaseous pressure in the chamber. 5. The syringe of claim 4, wherein the means for effecting the controlled build up of pressure in the chamber comprises a source of compressed gas connected to the chamber through a bleed valve. 6. The syringe of claim 3, wherein the upstream end of the chamber is covered by a filter element. 7. The syringe of claim 6, wherein the filter element is a semi-permeable membrane which allows the passage of gas but not of foreign matter therethrough. 8. The syringe of claim 6, wherein the filter element provides a sterile barrier. 9. The syringe of claim 1 further comprising a rupturable membrane arranged at, or substantially adjacent to, the upstream end of the nozzle to block passage therethrough, said membrane having an upstream side which faces the upstream end of the nozzle. 10. The syringe of claim 9, wherein the energizing means applies a gaseous pressure to the upstream side of the membrane sufficient to rupture the membrane and produce a supersonic gas flow through the nozzle. 11. The syringe of claim 1, wherein the source of particles is comprised of a sealed capsule containing said particles. 12. The syringe of claim 1, wherein the source of particles is comprised of first and second rupturable diaphragms which extend across the interior of the nozzle and contain said particles therebetween. 13. The syringe of claim 12 further comprising a third diaphragm disposed between the first and second diaphragms to provide at least two compartments for containing said particles. 14. The syringe of claim 12, wherein the first and second diaphragms are sealed together about their edges to form a sealed compartment for containing said particles. 15. The syringe of claim 12, wherein at least one of the diaphragms is dimpled away from the other to provide a space sufficient to contain a majority of the particles. 16. The syringe of claim 1 further comprising a removable seal covering the downstream end of the nozzle. 17. The syringe of claim 16, wherein the seal is comprised of a peelable foil. 18. The syringe of claim 1, wherein the nozzle further comprises a convergent section disposed upstream from the divergent downstream section. 19. The syringe of claim 1 further comprising a spacer element positioned at the downstream end of the nozzle, wherein said spacer element provides a fixed spacing between the downstream end of the nozzle and a target surface. 20. The syringe of claim 19, wherein the spacer element comprises a tubular shroud arranged in coaxial relation with the nozzle, said shroud having a downstream opening with a larger diameter than that of the downstream end of the nozzle. 21. The syringe of claim 19, wherein the spacer element is comprised of a solid tubular shroud arranged in coaxial relation with the nozzle such that a shock wave reflected from the target surface can be contained by said shroud. 22. The syringe of claim 21 further comprising a silencer element capable of receiving the reflected shock wave contained by the shroud and attenuating the intensity of energy associated with said shock wave. 23. The syringe of claim 22, wherein the silencer element is comprised of a sound attenuating medium which surrounds the tubular nozzle and receives the reflected shock wave from the shroud. 24. The syringe of claim 1 which is separable into upstream and downstream parts, wherein said downstream part comprises the nozzle and means for positioning a source of particles within the nozzle, and said upstream part comprises a portion of the energizing means. 25. The syringe of claim 24, wherein the downstream part is disposable. 26. The syringe of claim 25, wherein the downstream part further comprises a chamber arranged above the upstream end of the nozzle, said chamber having an upstream end covered by a filter element, and a downstream end which communicates with the upstream end of the nozzle. 27. A sterile package containing the disposable downstream part of claim 25. 28. The syringe of claim 1, wherein the gas flow is capable of delivering particles to a target surface at a velocity of 500 m/sec or greater.