초록 ▼

The invention relates to a needless syringe (1), comprising in succession, a gas generator (2), a gas expansion chamber (3) and a means for retaining the particles of an active agent, comprising at least one lid (8) which breaks under the influence of the gas coming from the generator (2). The main

The invention relates to a needless syringe (1), comprising in succession, a gas generator (2), a gas expansion chamber (3) and a means for retaining the particles of an active agent, comprising at least one lid (8) which breaks under the influence of the gas coming from the generator (2). The main characteristic of the inventive syringe (1) is that the tube (6) has a cylindrical upstream part in which the means retaining the particles are fixed, said upstream part having a substantially constant cross-section over a length that is more than twice its inner diameter.

대표청구항 ▼

1. A needleless syringe comprising, in succession, a gas generator (2), a gas expansion chamber (3, 23, 43), a means for retention of the particles of an active principle, comprising at least one protective seal intended to burst under the effect of the gases coming from said generator, and a tube (

1. A needleless syringe comprising, in succession, a gas generator (2), a gas expansion chamber (3, 23, 43), a means for retention of the particles of an active principle, comprising at least one protective seal intended to burst under the effect of the gases coming from said generator, and a tube (6, 26, 46) for ejection of said particles, characterized in that said tube (6, 26, 46) has a cylindrical upstream part in which the means for retention of the particles is fixed, said upstream part having a substantially constant cross section along a length that is more than twice its internal diameter.2. The needleless syringe as claimed in claim 1, characterized in that the expansion chamber (3, 23, 43) is continued by said upstream part of the tube (6, 26, 46), and the protective seal (8, 28, 48), which is the most upstream element of the means for retention of the particles, constitutes the limit between said chamber (3, 23, 43) and said tube (6, 26, 46).3. The needleless syringe as claimed in claim 2, characterized in that the protective seal (8, 28, 48) is calibrated to yield at a dynamic pressure, in the chamber (3, 23, 43), of at least 70 bar.4. The needleless syringe as claimed in claim, 2, characterized in that the ejection tube (6) is a straight cylinder.5. The needleless syringe as claimed in claim 4, characterized in that the gas expansion chamber (3) is substantially cylindrical and its internal diameter is close to that of the ejection tube (6).6. The needleless syringe as claimed in claim 5, characterized in that the diameters of the (expansion chamber (3) and of the ejection tube (6) are equal to 12 mm.7. The needleless syringe as claimed in claim 4, characterized in that the ratio of the sum of the lengths of the chamber (3) and of the tube (6) to their diameter is between 3 and 25.8. The needleless syringe as claimed in claim 2, characterized in that the expansion chamber (23) has a substantially cylindrical shape continued via a zone of narrowing (30) which opens into the ejection tube (26), such that the internal diameter of said tube (26) is smaller than the internal diameter of the cylindrical part of said chamber (23) and the protective seal (28) is fixed in the ejection tube (26) of reduced diameter.9. The needleless syringe as claimed in claim 8, characterized in that the zone of narrowing (30) is progressive, having a convergent nozzle shape.10. The needleless syringe as claimed in claim 8, characterized in that the ratio of the diameter of the cylindrical part of the expansion chamber (23) to the internal diameter of the ejection tube (26) is between 1.1 and 3.11. The needleless syringe as claimed in claim 8, characterized in that the ratio of the diameter of the cylindrical part of the expansion chamber (23) to the internal diameter of the ejection tube (26) is between 1.5 and 2.12. The needleless syringe as claimed in claim 2, characterized in that the downstream segment of the tube (46), through which the particles are ejected, has a divergent conical part (51) continued by a straight cylindrical part (52) whose free end comes into contact with the skin.13. The needleless syringe as claimed in claim 1, characterized in that the ratio of the length of the tube (6, 26, 46) to the length of the chamber (3, 23, 43) is between 1 and 5 and the sum of these two lengths is between 8 cm and 15 cm.14. The needleless syringe as claimed in claim 1, characterized in that the diameter of the particles of active principle is between 20 μm and 100 μm, and the total mass of said active principle is between 1 mg and 10 mg.15. The needleless syringe as claimed in claim 1, characterized in that the particles are accommodated between the protective seal (8, 28, 48) and a membrane (9, 29, 49) placed downstream of said protective seal (8, 28, 48).16. The needleless syringe as claimed in claim 1, characterized in that the compaction of the particles is between 1% and 70%.17. The needleless syringe as claimed in claim 1, characterized in that the density of the particles is between 1 and 18.18. The needleless syringe as claimed in claim 1, characterized in that the cylindrical upstream part of the ejection tube (6, 26, 46) has a substantially constant cross section along a length that is more than three and a half times its internal diameter.19. The needleless syringe as claimed in claim 1, characterized in that the gas generator comprises a reserve of compressed gas which can be placed in communication with the expansion chamber (3, 23, 43).