NEEDLELESS SYRINGE

PROBLEM TO BE SOLVED: To provide a needleless syringe, wherein only quiet operation of the syringe can deliver particles over the wide target tissue (e.g. the skin or mucosa) of a subject in reasonably even distribution. SOLUTION: A gas is supplied through a first convergence part 5 of the gas flow route within the syringe. This disperses the gas and reduces its pressure, and provides a gas region with lowered pressure. Then a payload of particles is drawn into the gas flow route from its outside, utilizing the lowered gas pressure, and is allowed to accompany the gas flowing through the gas route. At a second convergence part 9, the particles accompanying the gas flow are accelerated. Then at the downstream outlet of the nozzle, the particles accompanying the gas flow are substantially dispersed with the full width of the nozzle, and the gas flow direction is decided by this delivery nozzle which defines the gas flow route boundary. Thus a high payload of the particles can be delivered over a wide target tissue region. COPYRIGHT: (C)2010,JPO&INPIT