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(12) United States Patent ao) Patent No.: us 6,666,843 Bi
Alexandre et al. (45) Date of Patent: Dec. 23,2003
U.S. Patent Dec. 23,2003 Sheet 2 of 2 US 6,666,843 Bl
(54) NEEDLELESS SYRINGE WITH
TEMPORARILY RETAINED THRUSTING
(75) Inventors: Patrick Alexandre, Gray (FR);
Bernard Brouquieres, Toulon (FR);
Philippe Gautier, Le Plessis Pate (FR);
Denis Roller, La Ferte Alais (FR)
(73) Assignee: Crossject, Paris (FR)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 84 days.
(21) Appl. No.: 10/089,642
(22) PCT Filed: Oct. 23, 2000
(86) PCT No.: PCT/FR00/02943
§ 371 (c)(1),
(2), (4) Date: May 1, 2002
(87) PCT Pub. No.: WO01/32243 PCT Pub. Date: May 10, 2001
(30) Foreign Application Priority Data
Nov. 5, 1999 (FR) 99 13850
(51) Int. C I. A61M 5/30
(52) U.S. CI 604/69; 604/68
(58) Field of Search 604/69, 68, 82-89,
604/143, 181, 187, 244
(56) References Cited
U.S. PATENT DOCUMENTS
2,322,245 A 6/1943 Lockhart
The invention concerns the field of needless syringe for injecting liquid active principle for therapeutic purposes. It concerns a syringe wherein the active principle (1, 10) is initially placed between an injector (2, 22) comprising at least an injection duct (3, 23) contacted with the skin and a mobile wall (4, 24) separated from thrusting means (5, 25) displaced by gases of propellant generator (7, 27) pressurising and expelling the active principle. Said syringe aims at quickly providing a high expelling speed of the liquid to efficiently perforate the skin and improve bioavailability. Said syringe is characterised in that said thrusting means (5, 25) comprising temporary retention device (6, 26) deactivated by the operation of the propellant generator (7, 27).
9 Claims, 2 Drawing Sheets
NEEDLELESS SYRINGE WITH
TEMPORARILY RETAINED THRUSTING
The present invention concerns the field of needleless syringes used for intradermal, subcutaneous or intramuscular injections of liquid active principle for therapeutic use in human or veterinary medicine.
A needleless syringe is noninvasive by definition: there is no needle passing through the skin in order to bring the active principle to the place where it is to act. For a needleless syringe, it is necessary for the jet of liquid active principle emerging from an orifice or injection conduit to pierce the skin and penetrate to a greater or lesser depth depending on the type of injection desired: to do so, the jet must have a high speed. If the jet is too slow, there is no perforation of the skin, the liquid spreads across the surface of the skin, and it is lost because it produces no therapeutic effect.
In most syringes, the devices for delivering the liquid active principle through the injector are generally displaceable walls of the piston type or of the deformable membrane type which have to be displaced or deformed rapidly, with great acceleration, in order to quickly produce a high-speed jet for piercing the skin.
In patent U.S. Pat. No. 2,322,245, Lockhart describes needleless syringes whose displaceable wall is displaced or driven either by a compressed mechanical spring or by a compressed gas reserve. This drive device acts directly on a rod which impacts a delivery piston situated at a relatively large distance therefrom; the rod is accelerated over this distance by the release of the spring, it impacts the delivery piston, sets it in motion and displaces it quickly enough to atomize the active principle through quite a fine conduit and inject it.
By contrast, for syringes with a pyrotechnic drive, which are described in the same patent, or patents U.S. Pat. No. 3,802,403 and U.S. Pat. No. 4,124,024, the pyrotechnic charge acts directly on the delivery piston or by way of a bellows resting on said piston.
More recently, the patent application WO 95/03844, concerning needleless syringes, again takes up basically the same technique of an impact rod acting on a delivery piston. The impact rod is driven by a mechanical spring or a compressed gas reserve. The drive device is in a high-energy state, and it acts directly on the impact rod which is retained by a lock thereby preventing release of the spring or the compressed gas. During the whole storage period prior to use, the rod and the lock are greatly prestressed.
Opening said lock, directly or by way of a cam, releases the impact rod and the stored energy, which displace the movable components, and injects the liquid. The system changes from a high-energy level to a low-energy level at the end of injection. For disposable syringes, return to the initial state is not possible. Those syringes which are to be used several times comprise auxiliary devices for recompressing the spring and refilling the reservoir of liquid active principle or changing it.
Likewise, patent application WO 97/13537 describes a needleless syringe comprising a displaceable wall and a thrust means consisting of a rod with a piston head. The thrust means is set in motion when the force resulting from the gas pressure of the generator on the piston head is greater than the force resulting from the friction of the piston; the temporary retention thus realized by this equilibrium of the forces translates into quite a slow movement of the displaceable wall.
These devices have several disadvantages. The bioavailability obtained by these devices is not entirely satisfactory. Note that bioavailability is defined by the quantity of liquid actually injected in relation to the quantity initially filling the 5 reservoir of the syringe.
These devices are cumbersome and heavy since they need to be large enough to permit a relatively long course of travel for acceleration of the impact rod. Moreover, spring or compressed gas motors provided for storing a high level of energy for a considerable time prior to use will be structurally quite heavy. Moreover, these devices have problems relating to reliability. In the case of prolonged storage: the spring compressed to the maximum extent degrades; the compressed gas supply will be subject to leaks, and the highly prestressed lock may also experience operating dif15 Acuities. In all cases, these devices will be overdimensioned in an attempt to remedy the stated problems of reliability and they will therefore be a little more cumbersome and a little heavier.
The object of the invention is to increase the bioavail
20 ability of the active principle by improving the phase of acceleration of the liquid, and also to make available devices which are more compact and reliable.
The present invention concerns a needleless syringe for injection of a liquid active principle initially placed between,
25 on the one hand, an injector comprising at least one injection conduit, said injector being placed in contact with the skin or in immediate proximity to the skin of the subject to be treated, and, on the other hand, a displaceable wall initially separated from a thrust means displaced by the gases from
30 a gas generator and ensuring the pressurization and expulsion of the liquid active principle through the injector placed at the downstream end of the syringe, said syringe being such that said thrust means includes a temporary retention device deactivated by the functioning of the gas generator
35 initiated by a trigger member.
The thrust means is initially separated from the displaceable wall by a short distance which is determined in a manner which we will explain below. The functioning of the gas generator deactivates the temporary retention means,
40 abruptly displaces the thrust means to bring it into contact with the displaceable wall, thereby ensuring very rapid pressurization of the liquid and its injection at high speed. More precisely, the operator acts on a member which triggers the functioning of the gas generator, these latter
45 acting on the thrust means and in doing so deactivating the temporary retention device of said thrust means. By contrast, in the devices of the prior art, the operator acts (directly or indirectly) on a lock, which is a retention device, in order to release the energy necessary for the functioning of the
In this invention, liquid active principle will be understood essentially as a more or less viscous liquid, or a mixture of liquids, or a gel. The active principle will be able to be solid in the form of a powder in more or less
55 concentrated suspension in a suitable liquid. The granulometry of the solid and pulverulent active principle must be adapted, as must the shape of the conduit, to avoid blocking of the conduits.
Advantageously for this syringe, the temporary retention
60 device will be breakable: it will be broken upon functioning of the gas generator. Said temporary retention system will be calibrated, that is to say the rupture of the breakable temporary retention device will occur only when the thrust means is subjected, by the effect of the gases from the
65 generator, to a given force, depending in particular on the active principle and on the conditions of use, in order to very quickly obtain a jet of liquid moving at high speed.