WO1989007953A1

WO1989007953A1 - Improved vacuum-compression injector cartridge

Info

Publication number: WO1989007953A1
Application number: PCT/US1988/002373
Authority: WO
Inventors: Gasper L. Zuppardo
Original assignee: Vci Corporation
Priority date: 1988-02-26
Filing date: 1988-07-19
Publication date: 1989-09-08
Also published as: ES2011127A6

Abstract

An improved vacuum-compression injector medicament cartridge (100) for use in needleless hypodermic and hypomucosal injectors (30) incorporates a collar structure (115) that is self-aligning within the injector's cartridge-holding nozzle housing (41) and has perforations (117) to conduct vacuum-creating air flow which passes via an annular gap (45) between the cartridge body (103) and such housing (41), originating at a vacuum region surrounding the cartridge nozzle (113), and incorporating a laser-drilled nozzle orifice (111) for medicament injection.

Description

IHPROVED VACUUM-COMPRESSION

INJECTOR CARTRIDGE

This invention is in the field of needleless hypodermic and hyporucosal injectors using a vacuum to stabilize a nozzle of the device over the tissue to be penetrated. The present invention relates to an improved disposable medicament insert cartridge for use in such injectors; thusly simplifying use and manufacture, as well as facilitating disposability of the cartridge and its housing components and alignment of replacement cartridges within housings.

BACKGROUND OF THE INVENTION Needleless vacuum-compression injectors for hypodermic and hypomucosal applications are disclosed in U.S. Patent Nos. 4,403,609 and 4,421,508 to Cohen which show cylindrical medicament inserts for use therewith. For hygienic and sanitary reasons as well as for reasons of economy, it is desirable that components which contact bodily tissues and medicaments be disposable after use and replaceable for repeated use of the injector apparatus. Thus, the need exists not only for easy disposability and low cost of such components, but also for simple and reliable replacement capabilities that heretofore have involved delicate and accurate relative- alignment measures. 73

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SUMMARY

The present invention satisfies the above- indicated need for easy disposability, low cost, and reliable and easy replacement and alignment capabilities of medicament insert cartridges for vacuum-compression injectors by providing a low-cost disposable and replaceable cartridge that incorporates alignment features obviating the need for comparatively complex and expensive manufacturing alignment structures with tight tolerances within the housing, thusly further facil¬ itating low cost and disposability of such housing components. In particular, the cartridge of the present invention incorporates a perforated alignment collar which serves to seat it, during replacement, within a mating conical alignment bore of its housing, and which holds the cartridge concentrically and in correct alignment within such housing particularly during actuation of the injector and pressurization of cartridge contents. Perforations in the collar provide conduits for the vacuum-creating air flow from the annular gap between the cartridge and its housing to further conduits within the injector apparatus and eventually to the vacuum pump of the injector equipment. Additionally, the cartridge of the present invention incorporates a laser- drilled nozzle orifice of appropriately small diametrical size suited dimensionally and economically for the purposes of its function as well as its intended disposability.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, preferred embodiments thereof will be described with reference to the accompanying drawings wherein the same reference numerals have been used to designate the same parts in the various views. FIG. 1 is a schematic sectional view of a medicament cartridge according to the principles of the present invention;

FIG. 2 is a schematic end view of the cartridge shown in FIG. 1, as seen from the cartridge tip end; and, FIG. 3 is an enlarged schematic partial cross- section of a portion of the cartridge shown in FIGS.l and 2 depicted within adjacent portions of the injector as such injector components are assembled ready for use. DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Referring now to the drawings in detail, it will be seen, particularly in FIGS. 1 and 2, that the medicament cartridge 100 comprises a cartridge body 103 of a generally elongated hollow cylindrical shape and a sealing plunger plug 105 which is tightly slidably inserted within the bore 107. Cartridge body 103 comprises a cylindrical portion and includes barrel 123, a tip 113 at one end, and a collar 115 at the other end. A small-diameter orifice nozzle 111 is formed at one end of the cartridge body 103 within its tip 113 as appropriate for vacuum-compression injectors. A flange¬ like generally circular collar 115 is formed on the other end of cartridge body 103. Collar 115 is provided with one or more perforations 117, shown here as four annular sector-shaped openings communicating between the two faces of the collar, but which may be of any number and any variety of appropriate shapes including peripheral cut-outs in collar 115. Collar 115 is further provided with two or more ribs 119, shown here as four circumferentially-eguispaced and ra ially-oriented, parallel-sided gussets, whose outermost surfaces 121 are formed to fall substantially on an imaginary frusto- conical surface with its cone axis coinciding with the centerline of cartridge body 103. Outermost surfaces 121 of ribs 119 extend from the periphery of collar 115 to -4- the periphery of barrel 123 of cartridge body 103 in inclined manner, as shown. Ribs 119 may be of any number larger than one and may take the shape of axially oriented vanes, as shown, or of any other suitable form, such as for instance helical, spiral, etc., provided that at least portions of the ribs' outermost surfaces 121 fall on the described imaginary frusto-conical surface.

The cross-sectional view of FIG. 3 shows the portion of the medicament cartridge 100 that includes collar 115 mounted within the vacuum-compression injector 30 which is, for simplicity's sake, indicated only by portions of those injector components which are adjacent and which serve the mounting and actuation of the medicament cartridge when it is assembled within the injector.

FIG. 3 is thusly representative of and includes portions of the general structure of the injectors shown in FIGS. 1 of the referenced U.S. Patents to Cohen (4,403,609 and 4,421,508), which are incorporated herein -,y reference. For clarity's sake and wherever practical to facilitate understanding, the following description will utilize the same numerals as used in FIGS. 1 of Cohen's above patents to designate those Injector components with similar functions, even though such components may be modified in design to suit the purposes of the cartridge of the present invention.

As illustrated in FIG. 3, medicament cartridge 100 is mounted in the vacuum-compression injector in the bore of a generally cylindrical nozzle housing 41 that is provided with a threaded tapered base 39. The injector's exterior cylindrical housing 13 has interior threads 38 for threadably joining the tapered base 39 of nozzle housing 41. The right-hand end of a vacuum feed coupler 125, which is one of the internal injector components, is provided with a vacuum feed flange 129 that incorporates a face-sealing vacuum 'O'-ring 127 in an appropriate groove in its right-hand face. '0' ring 127 serves as a face seal between flange 129 and sealing face 131 of the tapered base 39 of the nozzle housing 41, as illus- trated. The vacuum feed coupler 125 is provided with a generally cylindrical coupler bore 137 on its axis and this bore is provided with an enlarged conical entry at its right-hand face which forms vacuum chamber 15. From the injector, which is otherwise not shown here, a piston rod plunger 23 protrudes toward the right through coupler bore 137 some small distance into the bore 107 of medicament cartridge 100 wherein it impinges on the left face of plunger plug 105.

The described assembled components provide conduits for passage of vacuum-creating air flow from the region surrounding tip 113 (shown in FIGS. 1 and 2) of the cartridge body 103 through annular passageway 45 between cartridge body 103 and nozzle housing 41, past spaces between ribs 119 of cartridge body 103, through perforations 117 in collar 115 of cartridge body 103, through vacuum chamber 15 and second annular passageway 51 formed between piston rod plunger 23 and coupler bore 137 in the vacuum feed coupler 125, and from there on into and through further conduits in the injector apparatus and eventually to the vacuum pump of the injector equipment. This passage of vacuum-creating air flow is indicated in FIG. 3 by schematic flow lines provided with directional arrows.

Cartridge 100, prefilled with medicament, is assembled, as shown in FIG. 3 within cylindrical nozzle housing 41 and within its tapered base 39 and is retained therein by the threaded engagement between tapered base 39 and exterior cylindrical housing 13 of the injector apparatus, whereby the injector's vacuum feed coupler 125 abuts and seals with its face seal vacuum 'O'-ring 127 -6- onto the sealing face 131 of tapered base 39. The right- hand face of vacuum feed flange 129 retains cartridge 100 in place. During assembly the injector's piston rod plunger 23 enters into bore entry 109 of bore 107 and impinges on or reaches close to the left face of plunger plug 105.

In operation of the injector, a vacuum pump draws air through the conduits described above and, on actuation of the injection mechanism, piston rod plunger 23 is driven toward the right-hand side into bore 107 of cartridge body 103 and pushes plunger plug 105 toward the right to pressurize and expel the cartridge's medicament content through nozzle 111 in tip 113 of cartridge body 103. It can be visualized that the motion and force of piston rod plunger 23 exerts a force toward the right onto cartridge 100 and thusly assists in seating it tightly with its collar 115 and ribs 119 seating within the mating counterbore 133 and within the mating taper bore 135 in tapered base 39. This seating action ensures correct relative alignment, concentricity and rigidity of seating between replaceable cartridge 100 and tapered base 29 in spite of likely dimensional differences due to relatively broad manufacturing tolerances and in spite of the need for relatively loose clearance fits of such disposable cartridges to facilitate quick replacement. It can be appreciated that the self-aligning properties of the present cartridge are of utmost importance not only for economy of manufacture, but primarily also in regard to the quick and easy replacement of disposable cartridges in use by persons not necessarily mechanically inclined or able or willing to apply special measures in assembly or disassembly of injectors in medical treatment situations requiring their fullest attention. Thus for instance, any jamming of a -7- cartridge within its mount during insertion or removal may result in the entire injector equipment being considered unusable and inoperative. It can be imagined that consequences of inoperative equipment in medical emergencies can be catastrophic.

Additionally, the cartridge 100 of the present invention, incorporating perforations 117 in its collar 115 as conduits for passage of vacuum-creating air flow, provides-for a significant reduction in tooling and parts complexity and thusly manufacturing cost in comparison with components providing similar functions in hitherto known vacuum-compression injectors. Known injectors have incorporated such vacuum-conduit facilities with housing structures, necessitating undercuts and various tooling coring measures which are costly in manufacturing. Such conventional housing structures are liable to jamming and lack non-jamming self-aligning capabilities when used in combination with conventional cartridges, particularly when desirable loose-tolerance manufacturing processes are applied. At the same time, such conventional configurations have been comparatively costly when used in disposable manner and they have not facilitated replaceability and ease of relative alignment as hereinabove described. Medicament cartridge 100 may be manufactured, for instance, by molding from a variety of plastic suited to medical uses as wella s from glass and other appro¬ priate materials. Mass production, for example by injection molding, has posed particular problems in the past in regard- to the manufacture of the small diameter orifice nozzle 111, as the small orifices, which are needed to be of the order of one to thirteen thousandths of an inch in diameter and in lengths between approx¬ imately twenty and sixty thousandths of an inch, are impractical if not impossible to mold reliably and economically. Consequently, past practice often had to resort to extremely costly micro-drilling operations, particularly in regard to smaller diameter orifices of greater depths which are essential for certain injector uses. It has been found that automated laser-drilling of appropriate nozzle orifices, subsequent to injection molding of the cartridges, provides highly reliable and accurate nozzle orifices at appropriately economical cost for disposability of cartridges of the present invention. For instance,' laser equipment manufactured and marketed by the company "Lambda Physik", of Goettingen, West Germany, has been found suitable for drilling of such nozzle orifices.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes and modifications in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. For use in a vacuum-compression injector, a medicament injection cartridge comprising: means for holding a medicament; a nozzle having a passageway connected to said means for holding a medicament and for having said medicament expressed therethrough; means to seal said medicament within said means for holding a medicament and to express said medicament from said means for holding a medicament through said nozzle; means for aligning and retaining said cartridge within said injector and incorporating a collar with an external peripheral surface at least in part of frusto- conical shape for mating with a substantially similar internal frusto-conical surface in said injector; and, one or more perforations in said collar communicating between upstream and downstream faces of said collar for conducting vacuum-creating air flow from a region surrounding the exit region of the body structure of said nozzle via an annular region surrounding said means for holding a medicament to a region downstream from said downstream face of said collar when said cartridge is assembled within said injector.

2. Apparatus of claim 1 wherein said collar comprises at least two gusset ribs.

3. Apparatus of claim 1 wherein said perforations are peripheral cut-outs in said collar.

4. Apparatus of claim 1 wherein said perforations are openings communicating between said upstream and downstream faces of said collar.

5. Apparatus of claim 1 wherein said nozzle is laser- drilled.

6. Apparatus of claim 5 wherein said nozzle is an orifice in a diameter range between one and thirteen thousandths of an inch having a depth range between twenty and sixty thousandths of an inch.

7. Apparatus of claim 6 wherein-said collar comprises at least two gusset ribs.

8. Apparatus of claim 1 wherein said nozzle is an orifice in a diameter range between one and thirteen thousandths of an inch having a depth range between twenty and sixty thousandths of an inch.

9. Apparatus of claim 1 wherein said collar incorporates means for spacing said cartridge from the surrounding structure of said injector, when said cartridge is assembled within said injector, to facilitate vacuum- creating airflow.