WO2022066921A1

WO2022066921A1 - Friction fit component for cartridges and medical injection device including the same

Info

Publication number: WO2022066921A1
Application number: PCT/US2021/051770
Authority: WO
Inventors: Raghuveer VEJERLA
Original assignee: Becton, Dickinson And Company
Priority date: 2020-09-25
Filing date: 2021-09-23
Publication date: 2022-03-31

Abstract

Provided herein is a cartridge holder subassembly for a medical injection device, the cartridge holder subassembly including a cartridge holder having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge holder interior, a cartridge having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge interior configured to hold a composition therein, and a friction fit component arranged between an interior surface of the cartridge holder sidewall and an exterior surface of the cartridge sidewall, the friction fit component configured to limit relative movement between the cartridge and the cartridge holder.

Description

FRICTION FIT COMPONENT FOR CARTRIDGES AND MEDICAL INJECTION DEVICE INCLUDING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to United States Provisional Application Serial No. 63/083,609, entitled “Friction Fit Component for Cartridges and Medical Injection Device Including the Same”, filed September 25, 2020, the entire disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The present disclosure relates generally to components useful as replacements for helical coil springs for medical devices, and, in particular embodiments or aspects, to injection devices including cartridge subassemblies with friction fit components.

Description of Related Art

[0003] Medical injection devices often utilize resilient members, such as springs, placed between various components, to bias the components in order to ensure more accurate drug delivery. However, there are shortcomings to the use of current resilient members used in medical injection devices, such as a lack of control and load recovery. Accordingly, there is a need in the art for a more robust component to allow for greater load recovery.

SUMMARY OF THE INVENTION

[0004] Provided herein is a cartridge holder subassembly for a medical injection device, the cartridge holder subassembly including a cartridge holder having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge holder interior, a cartridge having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge interior configured to hold a composition therein, and a friction fit component arranged between an interior surface of the cartridge holder sidewall and an exterior surface of the cartridge sidewall, the friction fit component configured to limit relative movement between the cartridge and the cartridge holder.

[0005] The friction fit component may include one or more protrusions arranged on the interior surface of the cartridge holder sidewall. The one or more protrusions may be integral to the cartridge holder. The one or more protrusions may be formed of the same material as the cartridge holder. The friction fit component may be a semi-circular or circular ring arranged around an outer circumference of the cartridge sidewall. The ring may be arranged about at least 10% of an outer circumference of the cartridge sidewall. The friction fit component may be formed of an elastomeric material. The elastomeric material may be a natural or synthetic rubber. The elastomeric material may be an elastomeric polymer or elastomeric copolymer. The cartridge may be formed of glass. The cartridge may include a stopper sealing the proximal end. The cartridge holder may be formed of plastic. The cartridge holder may include threads arranged at the distal end, with the threads configured for removable coupling to a needle hub. [0006] Also provided herein is a medical injection device including a cartridge holder subassembly, the cartridge holder subassembly including a cartridge holder having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge holder interior, a cartridge having an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge interior configured to hold a composition therein, and a friction fit component arranged between an interior surface of the cartridge holder sidewall and an exterior surface of the cartridge sidewall, the friction fit component configured to limit relative movement between the cartridge and the cartridge holder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 shows an exploded view of a cartridge holder subassembly with a friction fit component according to a non-limiting embodiment or aspect as described herein;

[0008] FIG. 2 is a partial cross-sectional view of a cartridge holder subassembly with a friction fit component according to a non-limiting embodiment or aspect as described herein;

[0009] FIG. 3 is a partial cross-sectional view of a cartridge holder subassembly with a friction fit component according to a non-limiting embodiment or aspect as described herein;

[0010] FIG. 4 is an exploded view of a medical injection device including a cartridge holder subassembly with a friction fit component according to a non-limiting embodiment or aspect as described herein; and

[0011] FIG. 5 is a cross-sectional view of a medical injection device including a cartridge holder subassembly with a friction fit component according to a non-limiting embodiment or aspect as described herein.

DESCRIPTION OF THE INVENTION

[0012] The use of numerical values in the various ranges specified in this application, unless expressly indicated otherwise, are stated as approximations as though the minimum and maximum values within the stated ranges are both preceded by the word “about”. As used herein, the term “about” means the stated value ± 10%. In this manner, slight variations above and below the stated ranges can be used to achieve substantially the same results as values within the ranges. Also, unless indicated otherwise, the disclosure of these ranges is intended as a continuous range including every value between the minimum and maximum values. For definitions provided herein, those definitions refer to word forms, cognates and grammatical variants of those words or phrases.

[0013] The figures accompanying this application are representative in nature, and should not be construed as implying any particular scale or directionality, unless otherwise indicated. For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. [0014] Provided herein is a cartridge holder subassembly with a friction fit component for use as a replacement for a spring in a medical device.

[0015] Turning to FIGS. 1-3, shown is a non-limiting embodiment or aspect of a cartridge holder subassembly for a medical injection device. Cartridge holder sub assembly includes cartridge 15, cartridge holder 14, and a friction fit component 11. When arranged inside a medical injection device, cartridge 15 is received within cartridge holder 14. In non-limiting embodiments or aspects, friction fit component 11 is arranged between cartridge 15 and cartridge holder 14.

[0016] Cartridge 15 has a proximal end, a distal end, and a sidewall therebetween defining an interior configured to hold one or more medications to be delivered with the medical injection device. Cartridge 15 can have an open proximal end. In non-limiting embodiments or aspects, open proximal end is sealed by a stopper configured to cooperate with a piston rod to eject one or more medications from the cartridge through distal end, for example through a needle arranged at a distal end of cartridge 15 that is in fluid communication with the cartridge interior. Cartridge 15 can assume any useful configuration, and can be formed of any suitable material. In non-limiting embodiments or aspects, cartridge 15 is glass or plastic. In one aspect or embodiment, cartridge 15 is formed integrally with friction fit component 11, although friction fit component 11 may be formed separately and have other configurations as discussed below. [0017] Cartridge holder 14 has an open proximal end, a distal end, and a sidewall therebetween defining a cartridge holder interior. Cartridge holder interior can be configured to receive a cartridge, such as cartridge 15, for example by inserting a cartridge into cartridge holder 14 interior through open proximal end of cartridge holder 14. In non-limiting embodiments or aspects, distal end of cartridge holder 14 includes one or more features to allow for a needle to be attached thereto. In non-limiting embodiments or aspects, distal end of cartridge holder 14 includes one or more of threads, protrusions, and/or recesses to cooperate with opposite features on a needle hub. Cartridge holder 14 can assume any useful configuration, and can be formed of any suitable material. In non-limiting embodiments or aspects, cartridge holder 14 is plastic. In one aspect or embodiment, cartridge holder 14 is formed integrally with friction fit component 11, such as co-molded dual shot feature, although friction fit component 11 may be formed separately and have other configurations as discussed below.

[0018] With continuing reference to FIGS. 1-3, cartridge holder subassembly can also include friction fit component 11. In non-limiting embodiments or aspects, friction fit component 11 is arranged between the exterior of the sidewall of cartridge 15 and the interior of the sidewall of cartridge holder 14, and provides friction to limit and/or prevent relative movement between cartridge 15 and cartridge holder 14 during device actuation, thereby ensuring a more accurate delivery of a composition from cartridge 15.

[0019] In non-limiting embodiments or aspects, friction fit component 11 is integral to cartridge holder 14, and is thus formed of the same material as cartridge holder 14 or exist as an elastomeric co-molded integral feature. In non-limiting embodiments or aspects, in which friction fit component 11 is integral to cartridge holder 14, friction fit component can be one or more protrusions configured to contact exterior surface of the sidewall of cartridge 15, to provide friction between cartridge 15 and cartridge holder 14. In non-limiting embodiments or aspects, friction fit component is attached to, but is not integral to, cartridge holder 14 and/or cartridge 15, and can be adhered to interior surface of the sidewall of cartridge holder 14 using any known, suitable adhesive. In non-limiting embodiments or aspects, friction fit component is adhered to inner surface of the sidewall of cartridge holder 14 with an adhesive, such as a hot-melt adhesive.

[0020] In non-limiting embodiments or aspects, friction fit component 11 is a distinct component, that is, friction fit component 11 is not integral to either cartridge 15 or cartridge holder 14. For example, and without limitation, friction fit component can be a component that is inserted into the interior of the cartridge holder to engage an outer surface of cartridge 15 and in inner surface of cartridge holder 14. In non-limiting embodiments or aspects, friction fit component 11 can have a circular or semi-circular shape, arranged about the outer circumference of the sidewall of cartridge 15, as shown in FIGS. 1 and 2. In non-limiting embodiments or aspects, friction fit component 11 is arranged about at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and/or 100%, all values and subranges therebetween inclusive, of the outer circumference of the sidewall of cartridge 15. In non-limiting embodiments or aspects, friction fit component can be formed of any suitable material that can provide sufficient friction to reduce and/or eliminate relative movement between cartridge 15 and cartridge holder 14, thereby ensuring a more accurate delivery of a composition from cartridge 15. Friction fit component can assume any useful shape/configuration, and can includes one or more undulations, protrusions, or the like, for example to increase surface contact with interior surface of sidewall of cartridge holder 14 and/or exterior surface of sidewall of cartridge 15. In non-limiting embodiments or aspects, more than one friction fit component 11 can be used. In one non-limiting embodiment or aspect, the cartridge holder 14 may have protrusions, slots, or openings that allow for locating or snapping the friction fit component 11 into a defined location axially on the cartridge housing.

[0021] In non-limiting embodiments or aspects, friction fit component is formed of an elastomeric compound, such as a rubber. In non-limiting embodiments or aspects, the rubber is polyisoprene rubber, silicone rubber, and/or butyl rubber. In non-limiting embodiments or aspects, the rubber is butyl rubber (IIR), isoprene rubber (IR), butadiene rubber (BR), styrenebutadiene rubber (SBR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), chlorosulphonated polyethylene (CSM), ethylene-vinyl acetate copolymer (EVA), styrene-isoprene rubber (SIR), thermoplastic elastomers, and/or natural rubbers.

[0022] In non-limiting embodiments or aspects, friction fit component 11 is formed of a elastomeric copolymer, including, without limitation, thermoplastic elastomers, thermoplastic vulcanizates, styrene copolymers such as styrene-butadiene (SBR or SBS) copolymers, styrene-isoprene (SIS) block polymers or styrene-isoprene/butadiene (SIBS), in which the content of styrene in the styrene block copolymer ranges from about 10% to about 70%, and preferably from about 20% to about 50%. The elastomer composition can include, without limitation, antioxidants and/or inorganic reinforcing agents to preserve the stability of the elastomer composition, a vulcanizing agent, a vulcanizing accelerator, a vulcanizing activator, a processing aid, a filler, etc. to maintain and improve the physical properties and heat resistance of the rubber material. [0023] In non-limiting embodiments or aspects, friction fit component 11 is formed of a material having a Shore A value of 20-40 optionally 30-40, all values and subranges therebetween inclusive. In non-limiting embodiments or aspects, friction fit component 11 is formed of a material comprising an ethylene propylene diene monomer (EPDM) rubber. In non-limiting embodiments or aspects, friction fit component 11 is formed of a material comprising an EPDM rubber, and various fillers/additives. In non-limiting embodiments or aspects, friction fit component 11 is formed of an ultra-high molecular weight EPDM rubber (e.g., KELTAN 9565Q), various fillers (e.g., MISTRON Vapor), mineral oil, zinc oxide, stearic acid, antioxidant(s) (e.g., SONGNOX 1076), curing accelerator(s) (e.g., TBzTD), vulcanizing agent(s) (e.g., VULTAC 710), and sulfur (such as a wettable sulfur).

[0024] In non-limiting embodiments or aspects, friction fit component 11 is formed of a foam.

[0025] Also provided herein is a medical injection device including a cartridge holder subassembly with a friction fit component as described above. Such devices, such as injection pens, are described in U.S. Patent No. 9,421,334, incorporated herein by reference in its entirety. With reference to FIGS. 4 and 5, shown are an exploded (FIG. 4) and cross-sectional (FIG. 5) view of an injection pen 51 for delivery of a composition to a user. As shown, injection pen 51 includes a pen upper body or housing 1, which houses a plurality of dose setting and injection components. Pen upper body 1 is connected to a cartridge housing 14, which houses cartridge 15. Injection pen 51 can also include a lower pen cap 12 to cover the cartridge 15 and cartridge housing 14 when injection pen 51 is not in use. As shown, injection pen 51 can include a dose set knob 2 that includes a knob-like portion that is rotated by a user to set a desired dose. Dose set knob 2 can also include a plurality of numerals, corresponding to a number of dosage units that is visible through a window 13 provided on pen upper body 1. A user rotates dose set knob 2 until the desired dose is visible in window 13. Pen upper body 1 can include an arrow or other indicator 53 to precisely indicate the set dose. Once the desired dose is set, a user presses a button 3 until the set dosage amount is completely injected. An outer shield 69 can cover a needle 56 to prevent accidental needle sticks upon removal of the lower pen cap 12.

[0026] Injection pen 51 can include push button 3, provided at a proximal end, closest to a user and farthest from needle 56, of pen upper body 1. Push button 3 can include an annular bead or rim 57 that engages with a corresponding annular groove (not shown) provided on the internal surface of dose set knob 2. The annular rim and groove connection can be a friction fit that maintains push button 3 in a biased position on dose set knob 2 under the force of a button spring 10, but allows push button 3 to be pushed into dose set knob 2 for injecting a set dose. The interior of push button 3 can accommodate a setback bearing insert 8 that rests on an internal surface at a proximal end of a setback member or driver 9. Push button 3 can be designed to rotate freely on setback bearing insert 8.

[0027] Setback member or driver 9 can be a cylindrical member, coaxial with and surrounded by dose set knob 2. Setback member 9 can be provided co-axially around brake tower 5 as described above. Brake tower 5 can be axially and rotatably fixed to pen upper body 1. In non-limiting embodiments or aspects, brake tower 5 co-axially surrounds a piston rod 6. Piston rod 6 can include a set of keys (not shown) that engage a slot (not shown) internal to brake tower 5 (as described above) to rotatably lock piston rod 6 to brake tower 5. Piston rod 6 can include a plurality of threads (not shown) provided on the interior surface thereof. Piston rod 6 can co-axially surround a lead screw 4 that includes a series of threads 42 at least at its distal end. Lead screw threads 42 can be configured to be in threaded engagement with the internal threads (not shown) provided on the interior of piston rod 6. Due to its threaded engagement with lead screw 4, piston rod 6 can be moved into cartridge 15 during injection to press on a stopper 16 provided inside cartridge 15 to expel a dose of medication.

[0028] With reference to the present disclosure, injection pen 51 includes a cartridge holder subassembly as described above. Cartridge holder subassembly includes cartridge 15, received within cartridge holder 14, and friction fit component 11 arranged to increase the friction between cartridge 15 and cartridge holder 14, to reduce and/or prevent movement of cartridge 15 during injection, and thus ensuring that an accurate dose is injected. As shown in FIG. 4, friction fit component 11 can be a ring, for example of an elastomeric material, arranged about an outer circumference of cartridge 15.

[0029] Following assembly, and when injection pen 51 is ready to be used, a dose for drug delivery can be set. To set a dose using injection pen 51 as described herein, a user rotates the knob portion of dose set knob 2 relative to pen upper body 1. An outer surface 59 of the dose set knob 2 can include a thread 23, which is in threaded engagement with a plurality of threads 17 provided on the internal surface of the pen upper body 1, as shown in FIGS. 4 and 5. Accordingly, as dose set knob 2 is rotated relative to pen upper body 1, dose set knob 2 screws or advances a distance out of pen upper body 1, as shown in FIG. 5. Dose set knob 2 can include an annular shoulder or rim 21 on the interior surface thereof near the proximal end, as shown in FIG. 5. This annular shoulder 21 can engage with an enlarged portion or head 91 of setback member 9, as shown in FIG. 5. Annular shoulder 21 of dose set knob 2 can include a series of teeth or ridges 22 that engage with a plurality of similarly shaped teeth or ridges (not shown) provided on enlarged head 91 of setback member 9. Dose set knob teeth 22 and setback member teeth can extend in opposite axial directions. During dose setting, dose set knob 2 can be free to rotate with respect to setback member 9 in both clockwise and counter-clockwise directions. As this occurs, the plurality of teeth or ridges 22 on dose set knob 2 can slip past the teeth provided on head portion 91 of setback member 9, thus providing a tactile signal or clicking noise to indicate the setting of a dosage amount.

[0030] With regard to the injection mechanism, as described above, lead screw 4 can include a plurality of threads 42 at its distal end that are in threaded engagement with a plurality of threads 64 that can be provided along the entire length of a hollow piston rod 6 as shown in FIG. 4. Piston rod 6 can be held non-rotatably with respect to pen upper body 1 due to a non- rotatable coupling with brake tower 5, which can be held axially and rotatably fixed with respect to the pen upper body 1. Piston rod 6 can include a key or set of keys 62 at its distal end that engage with a slot (not shown) provided on the internal surface of the brake tower 5 to prevent relative rotation therebetween while permitting piston rod 6 to move axially with respect thereto. Threads 42 of lead screw 4 can include a flat portion (not shown) corresponding to a flat portion 65 of piston rod 6, such that axial movement of the lead screw during dose setting does not result in axial movement of the piston rod 6. Accordingly, rotation of lead screw 4 during injection of a dose can cause the threads 42 of lead screw 4 to engage threads 64 of the piston rod 6, thereby axially moving piston rod 6. Because piston rod 6 can be non-rotatable with respect to body 1, as lead screw 4 is caused to rotate during injection, as described above due to its rotational coupling setback member 9, piston rod 6 through its threaded engagement with lead screw 4 can be caused to move in the distal direction to press against stopper 16 provided in cartridge 15, thus expelling a liquid medication therefrom.

[0031] Although the devices have been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the systems and methods are not limited to the disclosed embodiments, but on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present systems and methods contemplate that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

THE INVENTION CLAIMED IS

1. A cartridge holder subassembly for a medical injection device, comprising: a cartridge holder comprising an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge holder interior; a cartridge comprising an open proximal end, a closed distal end, and a sidewall therebetween defining a cartridge interior configured to hold a composition therein, the cartridge received in the cartridge holder interior; and a friction fit component arranged between an interior surface of the cartridge holder sidewall and an exterior surface of the cartridge sidewall, the friction fit component configured to limit relative movement between the cartridge and the cartridge holder.

2. The cartridge holder subassembly according to claim 1, wherein the friction fit component comprises one or more protrusions arranged on the interior surface of the cartridge holder sidewall.

3. The cartridge holder subassembly according to claim 2, wherein the one or more protrusions are integral to the cartridge holder

4. The cartridge holder subassembly according to claim 2 or claim 3, wherein the one or more protrusions are formed of the same material as the cartridge holder.

5. The cartridge holder subassembly according to any of claims 1-4, wherein the friction fit component comprises a semi-circular or circular ring arranged around an outer circumference of the cartridge sidewall.

6. The cartridge holder subassembly according to claim 5, wherein the ring is arranged about at least 10% of an outer circumference of the cartridge sidewall.

7. The cartridge holder subassembly according to any of claims 1-6, wherein the friction fit component is formed of an elastomeric material.

8. The cartridge holder subassembly according to claim 7, wherein the elastomeric material comprises a natural or synthetic rubber.

9. The cartridge holder subassembly according to claim 7, wherein the elastomeric material comprises an elastomeric polymer or elastomeric copolymer.

9

10. The cartridge holder subassembly according to any of claims 1-9, wherein the cartridge is formed of glass.

11. The cartridge holder subassembly according to any of claims 1-10, wherein the cartridge comprises a stopper sealing the proximal end.

12. The cartridge holder subassembly according to any of claims 1-11, wherein the cartridge holder is formed of plastic.

13. The cartridge holder subassembly according to any of claims 1-12, wherein the cartridge holder comprises threads arranged at the distal end, the threads configured for removable coupling to a needle hub.

14. A medical injection device comprising: a housing having a distal end and a proximal end; a cartridge holder subassembly according to any of claims 1-13 received within the housing; an injection needle at a distal end of the housing and in fluid communication with the cartridge; and an actuation member at a proximal end of the housing, the actuation member configured to actuate the medical injection device to deliver a composition through the injection needle, wherein the friction fit component limits movement of the cartridge relative to the cartridge holder.