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.

Abstract: A method of distributing particles in a flow of gas and a needleless syringe for use in the needleless injection of particles into the skin or mucosa of a vertebrate subject are disclosed. The syringe includes a convergence which reduces pressure of the gas flowing in the gas flow path due to the Venturi effect such that particles initially located outside of the gas flow path are drawn into the gas flow path under the action of the reduced pressure and become entrained in the gas. An exit nozzle accelerates the particles so entrained. In another aspect of the invention, there is provided a method of creating a gas flow in a needleless syringe which comprises flowing gas through a first convergence into a chamber to form a transsonic gas jet in the chamber and passing the gas jet from the chamber into a second convergence and along the nozzle.

Abstract: A needleless syringe particle delivery system is provided. The needleless syringe has an elongate nozzle that is connected at its upstream end to a sealed chamber. The sealed chamber contains gas at super-atmospheric pressure and particles of a therapeutic agent. Upon release of the gas from the sealed chamber, a flow is formed which entrains the particles and allows the particles to pass through the nozzle at supersonic speed for subsequent delivery to a target surface.

Abstract: There is disclosed a method of distributing particles in a flow of gas and a needleless syringe for use in the needleless injection of particles into the skin or mucosa of a vertebrate subject. The syringe has the advantage that no bursting membranes are required, reducing noise, and that the particles are substantially uniformly distributed in the gas stream. This is achieved by providing a convergence which reduces pressure of the gas flowing in the gas flow path due to the Venturi effect such that particles initially located outside of the gas flow path are drawn into the gas flow path under the action of the reduced pressure and become entrained in the gas. An exit nozzle is provided to accelerate the particles so entrained.

Abstract: A needleless syringe capable of accelerating particles comprising a therapeutic agent across skin or mucosal tissue of a vertebrate subject is provided. The syringe comprises a body having a lumen with a diaphragm located adjacent to a terminus thereof. Particles comprising a therapeutic agent are delivered from an external surface of the diaphragm by means of the motive force provided by the impact of a gaseous shock upon the internal surface of the diaphragm. A method for transdermally delivering particles comprising a therapeutic agent from the needleless syringe is also provided.

Abstract: A needleless syringe comprising a body containing a lumen, an upstream end of which is, or is arranged to be, connected to a source of gaseous pressure which can suddenly be released into the lumen; the downstream end of the lumen terminating behind a bistable diaphragm which is movable between an inverted position in which it presents outwardly of the body a concavity for containing particles of a therapeutic agent, and an everted, outwardly convex, position; the arrangement being such that, in use, when gas under pressure is released into the lumen, the diaphragm will snap over from its inverted to its everted position and catapult the particles outwardly.

Abstract: A needleless syringe capable of accelerating particles into a target surface is provided. The syringe comprises a body having a lumen with a diaphragm located adjacent to a terminus thereof. Particles are delivered from an external surface of the diaphragm by means of the motive force provided by the impact of a shockwave imparted to the internal surface of the diaphragm. A method for delivering particles from the needleless syringe is also provided.

Abstract: A needleless syringe capable of accelerating particles into a target surface is provided. The syringe comprises a body (20, 21, 22) having a lumen with a diaphragm (26) located adjacent to a terminus thereof. Particles are delivered from an external surface of the diaphragm (26) by means of the motive force provided by the impact of a shockwave imparted to the internal surface of the diaphragm. A method for delivering particles from the needleless syringe is also provided.

Abstract: A needleless syringe capable of accelerating particles comprising a therapeutic agent across skin or mucosal tissue of a vertebrate subject is provided. The syringe comprises a body having a lumen with a diaphragm located adjacent to a terminus thereof. Particles comprising a therapeutic agent are delivered from an external surface of the diaphragm by means of the motive force provided by the impact of a gaseous shock upon the internal surface of the diaphragm. A method for transdermally delivering particles comprising a therapeutic agent from the needleless syringe is also provided.

Abstract: A membrane filter having one or more ducts is disclosed herein. Each of the ducts has a porous wall defining a lumen surrounded by helical grooves in the respective wall. The groove can be a single, double, or triple start groove defining a flow direction along the groove. The cross sectional area of the groove in the case of a single start groove, or aggregate cross sectional area of the groove in the case of a double or triple start groove, perpendicular to the flow direction along the lumen is within a range of 75% to 125% of the cross sectional area of the lumen. The helical grooves create vortices which reduce concentration polarization while increasing membrane area.

Abstract: A needleless syringe particle delivery system is provided. The needleless syringe comprises an elongate nozzle which is connected at its upstream end to an open ended capsule chamber. The capsule chamber is configured to house and intimately enclose a nonrigid capsule containing particles of a therapeutic agent. An opening means is provided at the upstream end of the capsule chamber, and is used to pierce the upstream end of a capsule in the chamber. After the capsule is opened, an energizing means connected to the upstream end of the capsule chamber applies a gaseous pressure sufficient to force the particles out of the capsule and the open downstream end of the capsule chamber and thus to create through the nozzle a supersonic gas flow in which the particles are entrained.

Abstract: A needleless syringe capable of accelerating particles comprising a therapeutic agent across skin or mucosal tissue of a vertebrate subject is provided. The syringe comprises an elongate tubular nozzle having a bend along its length and is connected to or capable of connection to a suitable energizing means for producing in the nozzle a supersonic condition sufficient to cause delivery of the particles to a target surface. A method for delivering particles comprising a therapeutic agent from the needleless syringe is also provided.

Abstract: A needleless syringe, in which particles of a therapeutic agent are entrained in a high pressure gas flow, has a nozzle surrounded by a shroud silencer through which gas reflected from the target surface may be vented to atmosphere while retaining any particles reflected in the gas.

Abstract: A method and apparatus for effecting heat or mass transfer between two fluids through a membrane comprises a conduit for flow of one fluid, said conduit being at least partly defined by said membrane and the configuration of said conduit in a plane orthogonal to the general direction of flow varying periodically along the general direction of flow either inherently or in response to fluid pressure therein in such a manner that when said fluid is pulsated along the line of the general direction of flow a component of motion is induced therein which is mutually orthogonal to the surface of the membrane and general direction of flow. In preferred embodiments the conduit configuration varies periodically along the general direction of flow in order to give rise to separation and reattachment of flow at a multiplicity of zones within the conduit, whereby secondary flow is induced within said zones. The apparatus is particularly applicable to blood oxygenation and dialysis.