Needleless syringe provided with modular resorvoir

A needleless syringe (1) comprising several elements including a gas generator, a reservoir (5) formed by a tube (6) which is closed off by an upstream plunger stopper (7) and a downstream stopper between which the liquid active principle (9) is contained, said reservoir (5) being able to have a volume which can be varied by displacement of the downstream plunger stopper (8) in said tube (6), and an injection device (10), characterized in that

• i) the gas generator is a pyrotechnic generator having a pyrotechnic charge (3) and an initiation system,
• ii) the elements of said syringe (1) are arranged in such a way as to ensure, irrespective of the amount of active principle (9) contained in the reservoir (5), the injection of all of said principle (9) through the skin, by virtue of the production, at the outlet of the injection device (10), of a pressure profile of the type consisting of an intense phase to permit penetration of the principle (9) through the skin, followed by a less intense phase to ensure its passage through the latter.