Needleless syringe functioning with a double-composition pyrotechnic charge

• US 6,758,829 B2
• Filed: 10/16/2002
• Issued: 07/06/2004
• Est. Priority Date: 04/19/2000
• Status: Expired due to Term

• Current Assignee: Crossject SA
• Original Assignee: Crossject SA
• Inventors: Alexandre, Patrick, Roller, Denis, Cognot, Patrick, Lafforgue, Joel
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): Han, Mark K
• Application Number:
  US10/221,965
• Publication Number:
  US 20030135155A1
• Time in Patent Office: 629 Days
• Field of Search: 604/68, 604/69, 604/70, 604/71, 604/72, 604/73, 604/131, 604/140, 604/141, 604/143, 604/145, 604/187
• US Class Current: 604/69
• CPC Class Codes: A61M 5/2046 Media being expelled from injector by gas generation, e.g. explosive charge
• CPC Class Codes: A61M 5/30 Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules
• CPC Class Codes: C06B 25/18 the compound being nitrocellulose present as 10% or more by weight of the total composition
• CPC Class Codes: C06B 45/02 comprising particles of diverse size or shape
• CPC Class Codes: C06B 45/12 having contiguous layers or zones

Abstract

The technical field of the invention is that of pre-filled and disposable needleless syringes, used for intradermal, subcutaneous and intramuscular injections of liquid active principle for therapeutic use in human and veterinary medicine. The inventive syringes (1) are mainly characterised in that they function with a pyrotechnic charge (6) consisting of a mixture of powder with high burning rate and a powder with low burning rate. Indeed, the combustion of the powder with a high burning rate enables to communicate instantly, through a piston (3), a very high speed to the active principle (4), whereas the combustion of the powder with a low burning rate enables to maintain a threshold pressure level to proceed with the injection, so as to ensure that the active principle (4) penetrates through the skin. Thus, the injection is properly and homogeneously without any loss of active liquid (4).

Claims

1. A needleless syringe comprising, in succession, a pyrotechnic gas generator, at least one piston, a reserve of liquid active principle, and an ejection nozzle, characterized in that the pyrotechnic gas generator comprises a mixture of at least two different pyrotechnic charges.

2. The needless syringe as claimed in claim 1, characterized in that the pyrotechnic gas generator comprises a mixture of a first pyrotechnic charge and of a second pyrotechnic charge.

3. The needleless syringe as claimed in claim 2, characterized in that the first pyrotechnic charge is a gun powder and the second pyrotechnic charge is also a gun powder.

4. The needleless syringe as claimed in claim 3, characterized in that the first powder has a dynamic vivacity of greater than 8 (Mpa.s)^{31 1}.

5. The needleless syringe as claimed in claim 4, characterized in that the first powder has a burning thickness of less than or equal to 0.5 mm.

6. The needleless syringe as claimed in claim 4, characterized in that the first powder has a combustion time of less than 6 ms.

7. The needleless syringe as claimed in claim 4, characterized in that the ratio of the mass of the first powder to the total mass of the two powders is greater than 0.1.

8. The needleless syringe as claimed in claim 3, characterized in that the second powder has a dynamic vivacity which is less than 16 (Mpa.s)⁻

1 and which is systematically less than that of the first powder.

9. The needleless syringe as claimed in claim 8, characterized in that the second powder has a burning thickness of between 0.1 mm and 1 mm.

10. The needleless syringe as claimed in claim 8, characterized in that the second powder has a combustion time which is greater than 4 ms and which is systematic all greater than that of the first powder.

11. The needleless syringe as claimed in claim 8, characterized in that the shape function of the second powder is progressive.

12. The needless syringe as claimed in claim 8, characterized in that the shape function of the second powder is almost constant.

13. The needleless syringe as claimed in claim 3, characterized in that at least one of the two powders is based on nitrocellulose, the content by mass of which is between 0.45 and 0.99.

14. The needleless syringe as claimed in claim 13, characterized in that each powder based on nitrocellulose also contains nitroglycerin.

15. The needleless syringe as claimed in claim 3, characterized in that the first powder is chosen from among porous powders.

16. The needless syringe as claimed in claim 3, characterized in that the total mass of the two powders is less than 100 mg.

17. The needleless syringe as claimed in claim 1, characterized in that the pyrotechnic gas generator comprises an initiation device, involving a percussion device and a primer.