Title:  Needleless syringe

United States Patent:  6,210,359

Assignee:  Jet Medica, L.L.C. (Irvine, CA)

Filed:  January 21, 2000

A single use needless syringe for administering a fluid medication. The syringe comprises a hollow, tubular body which includes a gas storage portion defining a storage chamber containing a quantity of pressurized gas. The body also includes an ejector portion defining a piston chamber which is selectively placeable into fluid communication with the storage chamber and has a piston movably disposed therein. In addition to the gas storage and ejector portions, the body has a barrel portion defining a delivery chamber for receiving a prescribed dosage of the fluid medication, with the delivery chamber being oriented relative to the piston chamber such that the piston is advanceable into the delivery chamber. A discharge orifice of the body fluidly communicates with the delivery chamber and allows the fluid medication to be filled thereinto and expelled therefrom. The syringe further comprises a fracturable release member which is disposed within the body and normally prevents the flow of the compressed gas from the storage chamber into the piston chamber. Removably attachable to the body is a trigger mechanism of the syringe which includes a stem portion partially insertable into the body and engagable to the release member, and a head portion attached to the stem portion. The application of compressive pressure to the head portion subsequent to the insertion of the stem portion into the body facilitates the fracture of the release member and resultant flow of the pressurized gas into the piston chamber. The compressed gas acts against the piston in a manner forcing the piston into the delivery chamber which causes the fluid medication to be expelled therefrom via the discharge orifice.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a single use needleless syringe for administering a fluid medication. In the preferred embodiment, the syringe comprises a hollow, tubular body which itself includes a gas storage portion defining a storage chamber containing a quantity of a compressed gas. A preferred compressed gas used in the present syringe is carbon dioxide. In addition to the gas storage portion, the body of the syringe includes an ejector portion defining a piston chamber which is selectively placeable into fluid communication with the storage chamber and has a piston movably disposed therein. Also included in the body is a barrel portion defining a delivery chamber for receiving a prescribed dosage or quantity of the fluid medication, and a discharge orifice which is in fluid communication with the delivery chamber for allowing the fluid medication to be filled thereinto and expelled or ejected therefrom. In the body of the syringe, the delivery chamber is oriented relative to the piston chamber such that the piston is advanceable into the delivery chamber. Preferably disposed within the delivery chamber is a plunger member which prevents the fluid medication filled into the delivery chamber from flowing or migrating into the piston chamber.

The syringe of the present invention further comprises a fracturable release member which is disposed within the body and, prior to its fracture, prevents the flow of the compressed gas from the storage chamber into the piston chamber. Also included in the syringe is a trigger mechanism which is removably attachable to the body. The trigger mechanism itself comprises a stem portion which is partially insertable into the body and engagable to the release member. In addition to the stem portion, the trigger mechanism includes a head portion which is attached to the stem portion, and preferably integrally connected thereto.

In the operation of the needless syringe of the present invention, the application of compressive pressure to the head portion of the trigger mechanism subsequent to the insertion of the stem portion thereof into the body facilitates the fracture or breakage of the release member and resultant flow of the pressurized gas into the piston chamber. The compressed gas acts against the piston in a manner forcing the piston into the delivery chamber which causes the fluid medication to be expelled therefrom via the discharge orifice.

In the preferred embodiment of the present invention, the gas storage, ejector and barrel portions of the syringe body each have a generally circular cross-sectional configuration, with the storage, piston and delivery chambers defined thereby being disposed in coaxial alignment with each other. The body is preferably formed such that the diameter of the gas storage portion exceeds the diameter of the ejector portion, with the diameter of the ejector portion exceeding the diameter of the barrel portion. The source of compressed gas is preferably a compressed gas cartridge which is disposed within the gas storage portion of the body. The release member preferably comprises an integrally formed portion of the compressed gas cartridge, and more particularly an elongate quill thereof which extends axially into the piston chamber. The stem portion of the trigger mechanism is radially insertable into the ejector portion of the body so as to extend in generally perpendicular relation to the quill of the compressed gas cartridge. As a result, the application of compressive pressure to the head portion of the trigger mechanism subsequent to the insertion of the stem portion into the ejector portion of the body causes the stem portion to act against the quill in a manner which fractures the same and results in the flow of the compressed gas from the compressed gas cartridge into the piston chamber.

Since the trigger mechanism of the present needleless syringe is removably attachable to the body thereof, the syringe is well suited to being pre-filled with the fluid medication due to the reduced susceptibility thereof to accidental actuation or discharge during the process of manufacture, assembly, filling, and transport. Though the attachment of the trigger mechanism to the body can be deferred until the syringe is ready for use, the syringe is further preferably provided with a safety member which prevents the actuation of the trigger mechanism when the same is releasably attached to the body. The safety member has an arcuate configuration, and is slidably attached to the ejector portion of the body. The safety member has a slot formed therein, and is preferably sized to circumvent slightly greater than one-half the circumference of the ejector portion so as to be maintainable in engagement thereto. The safety member is movable back and forth along the ejector portion between locked and unlocked positions. When moved to the locked position, the stem portion is received into the slot and prevented from radial movement by the engagement of the head portion to the safety member itself. When the safety member is moved to the unlocked position, the application of compressive pressure to the head portion facilitates the radial movement of the stem portion towards the quill and fracture thereof by the force of the stem portion acting thereagainst.

In the present syringe, the body includes an outer surface and an inner surface having a proximal section which defines the storage chamber, an intermediate section which defines the piston chamber, and a distal section which defines the delivery chamber. The outer surface of the barrel portion of the body which defines the delivery chamber preferably includes measurement indicia applied thereto. The syringe further preferably comprises a reactive coating which is applied to the intermediate section of the inner surface and adapted to change color when exposed to the compressed gas flowing from the storage chamber into the piston chamber upon the fracture of the release member (i.e., the quill of the compressed gas cartridge) by the trigger mechanism. This reactive coating provides a quickly and easily discernable visual indication that the fluid medication has been discharged from the syringe. When the body is provided with the reactive coating, the same is preferably fabricated from a transparent or translucent material.

The compressed gas of the present syringe, which is preferably carbon dioxide, is preferably stored within the compressed gas cartridge in a liquified form. In addition or as an alternative to the body being provided with the above-described reactive coating, the compressed gas cartridge may be fabricated from a transparent or a semi-transparent material, thus allowing for the visual observation of the liquified compressed gas therein. The absence of the appearance of the liquified compressed gas within the compressed gas cartridge provides an indication that the syringe has been actuated, or has exceeded its shelf life in a manner resulting in all of the compressed gas being out-gassed therefrom. As will be recognized, when the transparent or semi-transparent compressed gas cartridge is provided in the present syringe, the body thereof is preferably fabricated from a transparent material.

The syringe may also be provided with a liner or sleeve which is disposed within the storage chamber and extends along the proximal section of the inner surface for preventing leakage or out-gassing of the compressed gas from within the storage chamber. A liner may also be disposed within the delivery chamber and extended along the distal section of the inner surface for maintaining the bioavailability of the fluid medication filled into the delivery chamber. This particular liner may be fabricated from an inert material which prevents interaction between the fluid medication and the material of the body, protects the fluid medication from exposure to air in the event the body material is permeable, and/or protects the fluid medication from exposure to ultraviolet radiation in the event it is photosensitive.

As an alternative to the use of the liner or sleeve within the delivery chamber of the body, the body itself may be fabricated from a material which is specifically suited to maintain the bioavailability of the fluid medication pre-filled into the delivery chamber, and thus extend the shelf life of the present syringe. In this respect, the selected material for the body of the syringe may be one which prevents the exposure of the fluid medication to ultraviolet radiation, is of low permeability to prevent the exposure of the fluid medication to air, or is inert to prevent any derogatory interaction with the fluid medication. In the event such selected material is of relatively low strength as could increase its susceptibility to bursting upon the fracture of the quill and release of the compressed gas into the piston chamber, the present syringe may be provided with an external, tubular reinforcement sleeve which is advanceable over the outer surface of the barrel portion of the body. The reinforcement sleeve is preferably cylindrically configured and formed such that when advanced over the barrel portion, it does not interfere with the engagement of the discharge orifice to the injection site on the user's skin. The sleeve may be fabricated from a material which magnifies the measurement indicia disposed on the barrel portion when advanced thereover.

Further in accordance with the present invention, there is provided a method of administering a needleless injection comprising the initial step of providing a needleless syringe having the above-described structural features. The syringe is preferably pre-filled with the fluid medication. The trigger mechanism is then attached to the body by partially inserting the stem portion thereof into the body. Thereafter, compressive pressure is applied to the head portion of the trigger mechanism to facilitate the fracture of the release member and resultant flow of the pressurized gas into the piston chamber.

Claim 1 of 29 Claims

What is claimed is:

1. A single use needleless syringe for administering a fluid medication, the syringe comprising:

a hollow, tubular body comprising:

a gas storage portion defining a storage chamber containing a quantity of a compressed gas;

an ejector portion defining a piston chamber which is selectively placeable into fluid communication with the storage chamber and has a piston movably disposed therein;

a barrel portion defining a delivery chamber for receiving a prescribed dosage of the fluid medication, the delivery chamber being oriented relative to the piston chamber such that the piston is advanceable into the delivery chamber; and

a discharge orifice in fluid communication with the delivery chamber for allowing the fluid medication to be filled thereinto and expelled therefrom;

a fracturable release member disposed within the body for preventing the flow of the compressed gas from the storage chamber into the piston chamber; and

a trigger mechanism removably attachable to the body and comprising:

a stem portion partially insertable into the body and engagable to the release member; and

a head portion attached to the stem portion;

wherein the application of compressive pressure to the head portion subsequent to the insertion of the stem portion into the body facilitates the fracture of the release member and resultant flow of the compressed gas into the piston chamber, the compressed gas acting against the piston in a manner forcing the piston into the delivery chamber which causes the fluid medication to be expelled therefrom via the discharge orifice.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.