GB2490111A

GB2490111A - Injection cartridge with movable seal

Info

Publication number: GB2490111A
Application number: GB1106443.3A
Authority: GB
Inventors: Ian Charles Cleathero
Original assignee: Medical House PLC
Current assignee: Medical House PLC
Priority date: 2011-04-15
Filing date: 2011-04-15
Publication date: 2012-10-24
Also published as: GB201106443D0

Abstract

A cartridge system for use in an injection device, comprising a cartridge body defining a medicament chamber 9; a needle assembly attachment hub 2 attachable to a forward end of said body and adapted to receive a needle assembly comprising a needle and a needle cover; first sealing means 7 axially moveable in said cartridge body by the application of a forward force thereto between a first position in which fluid communication between said medicament chamber and said needle assembly attachment hub is prevented, and a second position in which fluid communication between said medicament chamber and said needle assembly attachment hub is enabled by piercing with the rear end 11 of the needle; and second sealing means 8 adapted to seal the rear end of said medicament chamber. A further intermediate seal (14, see figure 9) may also be provided for a two-part medicament.

Description

CARTRIDGE SYSTEM

This invention rotates to the field of cartridge systems for use in injection devices, in particular but not exclusively autoinjectors, for storage and delivery by injection of a one-part medicament or for storage, reconstitution and delivery of a two-part medicament.

BACKGROUND

Some types of medicament for delivery by injection are provided and stored in a two-part form. The two-part medicament may have a solid component and a liquid component, for example there may be a powdered medicament and a liquid solvent or diluent. The powdered medicament may comprise a ground-down or milled solid medicament or may be a powder prepared by a lyophilisation process for example. The liquid part may be a second medicament, rather than a solvent or diluent. Alternatively, the two components might be two liquid components that need to be stored separately before use for compatibility reasons. Such two-part formulations are well known and sometimes referred to as "wet-dry" formulations. Immediately before the medicament is delivered by injection into the patient, the two components of the formulation are mixed together so that a combined medicament is delivered by the injection device.

The medicament is stored in a medicament cartridge which has at least two chambers to keep the respective medicament components separate from one another. Such cartridges have a generally cylindrical body with a narrowed distal end suitable for receipt of a needle assembly through which the medicament will ultimately be delivered.

The wider proximal end of the cartridge is initially open for filling with medicament.

The present invention is particularly but not exclusively concerned with applications wherein the dry medicament component is prepared by a lyophilisation or freeze-drying process. Lyophilisation processes are well-known and particular problems are documented, for example in W02009/043000 (Becton Dickinson and Company). One such problem is the filling of a medicament cartridge in preparation for the lyophilisation process. The dry component needs to be located at the forward or distal end of the cartridge; however the reduced diameter distal end makes the introduction of a stream of dry component therethrough difficult. The dry component is therefore usually supplied in liquid form through the rearward or proximal end of the cartridge and then subsequently lyophilised in situ to produce the dry component. Filling the cartridge with liquid medicament from the proximal end means that, during this process, the distal end orifice must be properly sealed. W020091043000 addresses the problem by providing a cartridge with a distal end of larger diameter, permitting dry filling therethrough.

In practice, the cartridges are typically filled and lyophilised in bulk, using a lyophilisation system such as that described, for example, in W0200911 53018 (Vetter & Co). Sterility of the cartridges must be maintained throughout. The result of the process is a plurality of sterile multiple-chamber cartridges, each containing a lyophilised dry component separated from a wet component.

Before the cartridges can be used, each must be assembled with a suitable injection device and fitted with a needle assembly at the distal end thereof. This involves at least two assembly stages, most likely by different parties at different locations. Commonly, with some types of injection device, the needle assembly is attached by the patient or user immediately prior to use of the device. In other types of injection device, for example some autoinjectors, the needle assembly is assembled with the cartridge before both are then assembled with the injection device.

The needle assembly contains a medicament delivery needle protected by a needle sheath and/or needle cover of known type in order to maintain sterility. Another problem is that, whereas the needle needs to be in fluid communication with the distal medicament chamber in order to deliver medicament, it is highly desirable to avoid having the needle in contact with the medicament prior to delivery of medicament, during storage of the device for example. During storage and before use of the injection device, it is also essential that the wet and dry components of the formulation are kept separate from one another within the injection device.

An autoinjector is an automatic injection device designed to facilitate automated delivery of a dose of medicament to a patient through a hypodermic needle, the injection usually being administered by the patient themselves. The injection can be delivered subcutaneously or intra-muscularly, depending upon the properties of the autoinjector.

An autoinjector works by delivering an injection automatically upon actuation by the patient, for example pressing a button, moving a lever or part of a housing etc. This is in contrast to a conventional manual syringe where the patient himself needs to directly depress a plunger into a barrel containing medicament in order to effect the injection.

The terms autoinjector" and injection device" are used interchangeably in the following description. Although the present disclosure contains reference to an autoinjector, it is envisaged that the present invention may be equally appflcable for use in other types of injecflon device.

In some prior art devices, mixing of the rnedicament is effected almost simultaneously with expulsion of the medicament from the device, the wet component being "flushed" through the dry component on its way out of the autoinjector. This has the advantage of reducing the total time between the user actuating the device and delivery of the injection. However, potentially there is a disadvantage in such "flushing" action, for example if mixing of the components is not homogenous, or W some of the dry component is left behind inside the device. incomplete mixing can also result in a blockage of the injection needle.

Generally, in a wet-dry autoinjector, the dry chamber containing the solid medicament powder also contains a volume of air or other gas which is replaced by the liquid medicament entering therein when the medicament is reconstituted or mixed. Any excess gas has to be "bled" or vented" from the chamber before injection takes place, else the device would undesirably inject an unacceptable volume of gas into the patient as welt as the reconstituted medicament. in addition, excess gas in the chamber may cause bubbling or foaming during mixing and/or injection (again with the risk of injecting unwanted gas into the patient).

it is an object of the present invention to provide an injection device and medicament cartridge for use therein which seek to mitigate at least some of the problems outlined above.

BRIEF SUMMARY OF THE DISCLOSURE

In accordance with a first aspect of the present invention there is provided a cartridge system for use in an injection device comprising: a cartridge body defining a medicament chamber; a needle assembly attachment hub attachable to a forward end of said body and adapted to receive a needle assembly comprising a needle and a needle cover; first seating means axially moveable in said cartridge body by the application of a forward force thereto between a first position in which fluid communication between said medicament chamber and said needle assembly attachment hub is prevented and a second position in which fluid communication between said medicament chamber and said needle assembly attachment hub is enabled by the piercing of said first sealing means by the rear end of said needle; second sealing means adapted to seal the rear end of said medicament chamber.

Preferably, said needle assembly attachment hub includes connector means capable of snap-fitting said hub to the forward end of said cartridge body.

Said needle assembly attachment hub preferably includes an elastomer seal capable of sealing the front end of said hub to define a needle assembly attachment hub chamber between said elastomer seal and said first axially-moveable sealing means. Preferably, the said needle assembly attachment hub includes one or more venting holes capable of venting said needle assembly attachment hub chamber. The venting holes are preferably sealed closed by the needle cover of a needle assembly comprising a needle and a needle cover and openable upon removable of said needle cover.

In a preferred form, said piercing is enabled by the application of a forward force to said first sealing means.

In a further embodiment, the system further comprises intermediate sealing means axially moveable in said cartridge body and adapted to separate said medicament chamber into a first sub-chamber and a second sub-chamber with no fluid communication therebetween. This enables the cartridge system to be used with a two-part medicament. For example, said first sub-chamber may contain a lyophilised medicament component.

The cartridge system is suitable for use in an injection device for delivering reconstituted two-part medicament. Alternatively, the cartridge is a standard glass medicament cartridge with a narrowed front end.

The cartridge system preferably further comprises a needle assembly, including a needle and a needle cover, received in said needle assembly attachment hub such that said needle is not in fluid communication with said medicament chamber. In said first position, the rear end of said needle is preferably not in contact with said first sealing means. Alternatively, in said first position, the rear end of said needle is staked in said first sealing means.

According to a second aspect of the present invention there is provided an autoinjector including a cartridge system as described in any of the preceding paragraphs.

Other features are described in the appended claims.

BRIEF DESCRiPTION OF THE DRAWiNGS

Preferred embodiments of the present invention wifl now be more particularly described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of part of medicament cartridge system embodying one aspect of the present invention; Figure 2 is a cross sectional side view of the medicament cartridge of Figure 1, without the needle attachment hub and needle assembly in place; Figure 3 is a cross sectional side view of the medicament cartridge system of Figure 1 with the needle cover in place; Figure 4 shows the rnedicament cartridge system of Figure 3 with the needle cover removed; Figure 5 shows the medicament cartridge system of Figure 4 when forward force is initially applied; Figure 6 shows the medicament cartridge system of Figure 5 upon continued application of forward force to deliver medicament; Figure 7 shows the medicament cartridge system of Figure 6 after complete delivery of medicament; Figures 8-10 are cross sectional views of a part-assembled medicament cartridge according to a second embodiment of the invention; Figure 11 shows the medicament cartridge of Figure 8 assembled with a needle assembly; and Figure 12 shows further detail of the needle assembly of Figure 11.

DETAILED DESCRIPTION

Throughout this application, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other components, integers or steps.

Throughout this application, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Throughout this application, reference to a "forward" direction means the direction which is towards the patient when the injection device is in use. The "forward" or "distal" end of the injection device is the end nearest the patient's skin when the device is in use.

Similarly, reference to a "rearward" direction means the direction which is away from the patient and the "rearward" or "proximal" end of the device is the end furthest from the patient's skin when the injection device is in use.

Throughout this application, reference to a "wet component of the medicament" means any liquid medicament, solvent, diluent, gel or other substantially liquid component.

"Wet" does not imply a complete absence of any solid matter.

Throughout this application, reference to a "dry component of the medicament" means any solid, powder or other substantially dry component. "Dry" does not imply a complete absence of liquid, and the dry component may comprise a stiff paste or slurry for example. Alternatively, the "dry" component may be replaced by a second liquid component.

Throughout this application, references to "reconstitution" include the term "mixing" wherein components of a medicament are mixed together with no solution, reaction or other chemical process necessarily taking place.

Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Referring to Figure 1, a medicament cartridge I has mounted, at its narrowed front end, a needle attachment hub 2 comprising a moulding with snap-fit connector means for clipping the hub to the front end of the cartridge. The needle attachment hub 2 receives a needle assembly 3 comprising a needle (not visible in Figure 1) protected by a needle cover 4. An elastomer seal 5 within the needle attachment hub 2 seals onto the needle cover 4 so that the front end of the illustrated assembly can be terminally sterilized. As further described below, the autoinjector device into which the illustrated cartridge system will ultimately be mounted need not be sterilized since the needle and medicament within the cartridge are maintained as sterile by the cartridge system of the present invention.

Figure 2 shows internal detail of the cartridge 1 without the needle assembly and needle attachment hub in place. The cartridge may be an entirely standard glass medicament cartridge. The cartridge body includes a narrowed front end 6 onto which the needle attachment hub can be fitted as described above. The cartridge body contains first (front) 7 and second (rear) 8 sealing means, preferably in the form of axially-moveable elastomeric seals or stoppers, with a medicament chamber 9 defined therebetween.

The second sealing means 8 seals the rear end of the cartridge I so that, in combination with the elastomer seal 4 within the needle attachment hub 2, the medicament and needle are contained within a sealed package that can be sterlized before insertion into an autoinjector device (thus avoiding the need for the entire autoinjector device to be sterilized).

As shown in Figure 3, the needle 10 is a double-ended needle whose front end is conventionally located within the needle cover 4. The rear end is located within a needle attachment hub chamber 11 defined between the elastomer seal 5 and the first sealing means 7. Typically the rear end of the needle would be located close to, but not touching, the first sealing means. However, in some embodiments it may be desirable to have the rear end of the needle staked in, but not through, the first sealing means. In either embodiment it can be seen that the needle is, initially, not in fluid communication with the medicament chamber 9. The needle cover seals into the front end of the needle attachment hub. The assembly as illustrated in Figure 3 can be mounted within an autoinjector device (not illustrated) for delivery of medicament.

When it is desired to deliver a dose of medicament, the needle cover is removed as illustrated in Figure 4. Removal of the needle cover may optionally uncover one or more venting holes 12 present in the needle attachment hub 2 to facilitate axial movement of the first sealing means 7 (further described below) by avoiding pressurisation of the needle attachment hub chamber 11.

Upon actuation of the autoinjector to deliver medicament, a forward force is applied to the second (rear) sealing means 8, the force being transmitted through the incompressible medicament in the chamber 9 to the first sealing means 7. The first sealing means is pushed onto the needle 10 so as to create a fluid path through the needle for the medicament which can exit to the injection site as illustrated in Figures 5 and 6. During delivery of medicament, the second sealing means 8approaches the first sealing means 7 until they meet, as illustrated in Figure 7, when delivery of the medicament is complete.

In general, an autoinjector device includes a needle which is located within a housing of the device. Upon activation of a force-generating source, a portion of the needle extends out of the housing and penetrates the outer layer of skin to deliver medicament.

An improved autoinjector is described in our international patent application, published under number WO 2005/070481. This device requires that the needle is moved axially so that it can appear beyond the end of the nozzle (the penetration stage) and for the duration of the injection, after which the needle retracts automatically (the retraction stage), so that it is never in sight of the user. The device also requires that the plunger is moved axially so that medicament is ejected (the injection stage). The overall complexity of the autoinjector is significantly reduced by both of these requirements (penetration and injection) being effected by one component, namely an inner housing (having reference numeral 7 in WO 2005/070481).

A medicament cartridge, plunger rod and needle assembly can be provided within the autoinjector. The medicament cartridge is supported in the autoinjector by a cartridge carrier. The distal end of the autoinjector comprises a front housing in which a return spring is located and a removeable end cap.

The medicament cartridge and needle assembly may be as described above with reference to Figures 1-7. Alternatively, a second embodiment of the medicament cartridge and filling thereof will now be described in more detail with reference to Figures 8-12. The second embodiment is suitable for use with a two-part medicament and lyophilisation process. The medicament cartridge illustrated in Figure 8 is generally cylindrical and defines a medicament chamber 9 having an external bypass feature 13 of known type. A medicament cartridge having an internal bypass may equally well be used. The cartridge has a narrowed distal end to which a needle attachment hub and needle assembly can be attached. The initially empty cartridge is provided with first sealing means 7 in the form of a stopper which prevents fluid communication between the needle attachment hub and the medicament chamber 9. With the cartridge in a vertical orientation, as illustrated in Figure 8, the presence of the stopper 7 allows the medicarnent chamber 9 to be filled with liquid medicament. The cartridge containing liquid medicament can then be placed in conventional lyophilisation apparatus, resulting in a dry powder medicament located immediately behind stopper 7.

Provision of the stopper 7 means that the medicament component for lyophilisation can be loaded into the preferred proximal end of the cartridge and sterility can be maintained throughout.

After lyophilisation, as shown in Figure 9, an intermediate sealing means 14 in the form of stopper is placed into the medicament cartridge so that the lyophilised medicament component is contained within a first sub-chamber 9a defined between the stoppers 7, 14.

Once the intermediate stopper 14 is in place, and with the cartridge still in a vertical orientation, the cartridge can be filled with a liquid medicament component. Next, as shown in Figure 10, a second sealing means 8 in the form of a stopper is placed into the cartridge so that the liquid medicament component is contained within a second sub-chamber 9b defined between the stoppers 14, 8.

Next, as shown in Figure 11, the cartridge loaded with medicament can be assembled with a needle attachment hub 2 and needle assembly 3.

Figure 12 shows further detail of the needle attachment hub 2 and needle assembly 3, using the same reference numerals as for the embodiment of Figures 1-7.

A significant advantage of the present invention is that a medicament cartridge system can be assembled, independently of the autoinjector device into which it will ultimately be installed, the cartridge system containing a sealed and loaded medicament cartridge, a sealed needle assembly and a plunger rod. The medicarnent and needle are isolated from one another and stored in a sterile condition. The medicament cartridge system can be loaded into the autoinjector at a later date, perhaps in a different location, and the need to sterilise the autoinjector once fully assembled is eliminated.

The cartridge system of the present invention is particularly advantageous for the storage of a lyophilised medicament because of the ease with which a sub-assembly (the cartridge, needle attachment means, first sealing means and intermediate sealing means) can be provided for the lyophisaUon process, the remaining components (allowing for provision of the liquid medicament) being assembled after the lyophilisation process is complete.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A cartridge system for use in an injection device comprising: a cartridge body defining a medicament chamber; a needle assembly attachment hub attachable to a forward end of said body and adapted to receive a needle assembly comprising a needle and a needle cover; first sealing means axially moveable in said cartridge body by the application of a forward force thereto between a first position in which fluid communication between said medicament chamber and said needle assembly attachment hub is prevented and a second position in which fluid communication between said medicament chamber and said needle assembly attachment hub is enabled by the piercing of said first sealing means by the rear end of said needle; second sealing means adapted to seal the rear end of said medicament chamber.
2. The system of claim I wherein said needle assembly attachment hub includes connector means capable of snap-fitting said hub to the forward end of said cartridge body.
3. The system of any of the preceding claims wherein said needle assembly attachment hub includes an elastomer seal capable of sealing the front end of said hub to define a needle assembly attachment hub chamber between said elastomer seal and said first axially-moveable sealing means.
4. The system of claim 3 wherein said needle assembly attachment hub includes one or more venting holes capable of venting said needle assembly attachment hub chamber.
5. The system of claim 4 wherein said venting holes are sealed closed by the needle cover of a needle assembly comprising a needle and a needle cover and wherein said venting holes are openable upon removable of said needle cover.
6. The system of any of the preceding claims wherein said piercing is enabled by the application of a forward force to said first sealing means.
7. The cartridge system of any of the preceding claims further comprising intermediate sealing means axially moveable in said cartridge body and adapted to separate said medicament chamber into a first sub-chamber and a second sub-chamber with no fluid communication therebetween.
8. The cartridge system of claim 7 wherein said first sub-chamber contains a lyophilised medicament component.
9. The cartridge system of claim 7 or claim 8 for use in an injection device for delivering reconstituted two-part rnedicament.
10. The cartridge system of any of claims 1-6 wherein said cartridge is a standard glass medicament cartridge with a narrowed front end.
11. The cartridge system as claimed in any of the preceding claims further comprising a needle assembly, including a needle and a needle cover, received in said needle assembly attachment hub such that said needle is not in fluid communication with said medicament chamber.
12. The cartridge system of claim 11 wherein, in said first position, the rear end of said needle is not in contact with said first sealing means.
13. The cartridge system of claim 11 wherein, in said first position, the rear end of said needle is staked in said first sealing means.
14. A cartridge system substantially as described herein with reference to and as illustrated in any appropriate combination of the accompanying drawings.
15. An autoinjector including a cartridge system as claimed in any of the preceding claims.
16. An autoinjector substantially as described herein with reference to and as illustrated in any appropriate combination of the accompanying drawings.