The present invention is an auto-injector for the administration and self-administration of drugs by subcutaneous, intramuscular or intra-dermal injection and for drug solutions or suspensions. This application describes an injection system that may be used by the patient for self-injection or by a medical professional.
Auto-injectors automate the injection stroke alleviating the need for the patient or professional to actuate the plunger rod.
The auto-injector according to the present invention comprises in an outer casing that holds a standard cartridge comprising a barrel with a drug contents being contained by a movable plunger or stopper at one end, and a seal or septum and metal crimp or cap to hold said septum in place at the other end.
A biased means that pushes against the movable plunger or stopper of the cartridge thus pressurizing the drug contents. A needle shuttle is held within casing comprises two needles that are attached and connected to each other, the first needle being the injection needle and the second needle being the septum needle. A means or shoulder retains the cartridge in its correct position when inserted and prevents it from being pushed against the needle shuttle. A needle guard is connected to the casing, being biased outwards by a spring or the like such that the needle is always covered by the needle guard, thus hiding the needle before and after the injection.
The auto-injector according the present invention may further comprise a needle guard locking mechanism that prevents the needle guard from being pushed back a second time, thus preventing needle stick injuries after use.
The auto-injector may further comprise an indicator. The indicator may be in form of an indicator rod that is attached to the biased means or the movable plunger or stopper and thus moves with it, thus allowing to indicate the progress of the injection progress. The indicator rod may be connected and used to operate any other indicator such as a rotary indicator or an electronic indicator or a connectivity device.
In one embodiment, the indicator extends beyond the rear casing to a distance determined by the fill volume and enabling the user to monitor the status of the injection.
In a preferred embodiment, the indicator rod has a closed end and contains the spring within. The outer casing comprises a portion that allows to monitor the progress and status of the injection progress, for example a cap which is transparent or has viewing windows. If the drug volume is fully injected, the indicator is no longer visible indicating end of injection. Placing the spring inside the indicator has the advantage that the spring can be longer than if the indicator is placed inside the spring or the device may be shorter. A longer spring means a higher mean force which is advantageous for viscous drugs.
The invention further relates to a modular designed auto injector which is composed of several sub-assemblies or modules. For ease of assembly, the modular auto-injector comprises three sub-assemblies, namely a cartridge, a power source and indicator sub-assembly and a needle and needle guard sub-assembly.
The cartridge sub-assembly comprises a barrel, a drug volume that is bounded by a plunger and a crimped septum.
The power source and indicator assembly comprises a biased means or spring and an indicator rod that is held within a rear casing. The invention allows for the cartridge to have a variable fill volume when assembled with the power source and indicator sub-assembly.
In order to indicate the status and progress of the injection process, the indicator rod may be connected to either the biased means or spring or to the movable plunger or stopper upon assembly of the device in a way that it moves with it.
If the biased means is a spring it may further comprise a spring locking member. In this case the power source and indicator assembly may further comprise a second weaker spring to pressurize the cartridge drug contents prior to injection while the first spring is locked by the spring locking member. The second spring also avoids a pressure pulse when the second spring is released.
The needle and needle guard sub-assembly comprises a front casing holding a needle shuttle with an injection needle and a septum needle, the shuttle being held within the casing a needle guard for preventing needle stick injuries that is biased outwards by a spring, a locking mechanism that prevents the needle guard from being pushed back a second time, and a means to retain the cartridge in its correct position when inserted.
The injection needle and the septum needle may have the same diameter or gauge or have different diameters or gauges. They may have the same type of bevel tip or different types of bevel tip. For example, to minimize injection time the septum needle may be of larger diameter or smaller gauge than the injection needle. For simplicity a single needle may be used with two sharp ends or bevels. Different needle gauges and/or bevels can be used to ensure the injection needle penetrates the injection site before the septum needle penetrates the septum to ensure a full injection. The interchange of the injection needle allowing adaption for subcutaneous, intramuscular or intra-dermal injection.
The modular auto-injector may be assembled by an easy two-step process such as placing the cartridge into the needle and needle guard sub-assembly followed by connecting it with the power source and indicator sub-assembly in a way that the drug contents in the cartridge are pressurized. If the device is intended for single use, any connection means to lock the sub-assemblies of the modular auto-injector together may be used, such as a snap fit.
In a preferred embodiment, the modular auto-injector can be re-assembled or is multiple use. In this case the needle and needle guard assembly and the power source and indicator assembly may be connected by a a bayonet fit or a screw or are hinged together to allow a reversible connection. In addition, the biased means of the power source and indicator assembly allows for a multiple use such as an electric motor, a liquified gas canister or a spring with means to re-compress the spring. Finally, the needle and needle guard assembly comprises a seal and a removable needle cap that always keep the needles and the cartridge septum sterile.
The embodiments of the auto-injector according to the present invention may be assembled under sterile conditions or may be submitted to terminally sterilization after assembly.
If the drug in the cartridge is a small molecule (non-biologic) the assembled device may be terminally sterilized in a blister or pouch using gas, vapor or radiation such as gamma ray, e-beam or any other.
When sterilizing the device with sensitive drug contents such as biologic drugs, the blister/pouch with the assembled device has at least a portion made from gas permeable material. The device may have gas pathways to assure that the needles and the external surface of the cartridge septum are sterilized. The device can then be placed in a gaseous environment such as ethylene oxide or nitrogen dioxide for sterilization.
To prevent the gas affecting sensitive drug contents, the cartridge assembly may preferably have gas impermeable components, in particular plunger/stopper and septum/cap. The gas used should preferably not be at elevated temperatures and preferably below body temperature and preferably below 36° C.
The device may be supplied as a ready-to-use medical device or supplied pre-assembled as a combination product (“kit”) for self-assembly by the user.
Sterilisation may take place before assembly or after assembly in which case it is terminally sterilized. If sterilized before assembly only the needle and guard sub-assembly or module 182 need be sterilized. The assembled device may be terminally sterilized in a blister or pouch. A needle cap and maybe a seal is required if the device is sterilized outside a blister. If the device is assembled by the user, the cartridge can be supplied in a blister or with no blister in which case the septum needs to be wiped with ethanol before device assembly.
Table 1 shows an overview of the different options as regards sterilization, options 3 to 6 allowing for re-assembly.
The auto-injector according to the present invention may be used with drug suspensions or solutions and API's or biologics. If the suspension is unstable with settling tendencies the cartridge needs to be shaken before use to re-mix.
The modular design has the advantage that each sub-assembly may be produced separately under conditions individually adapted. It further allows for flexibility in production and allows different auto injectors to share modules. The modular design also allows for part exchangeability which bears the additional advantage is that modules or sub-assemblies can be interchanged to change the characteristics of the auto-injector. For instance, by changing the needle and hub and needle guard assembly the device can be changed from a subcutaneous auto-injector to an intramuscular or intra-dermal auto-injector. It also allows for the power source module to be a reusable device. The modular designed auto-injector does also allow the cartridge to be exchanged, either after it has been used or if its shelf-life has expired.
The present invention allows for the use of industry standard injection cartridge and manufacture auto-injectors with a dry needle during storage and with various other advantages.
With reference to the figures, specific embodiments of the present invention are described hereinafter:
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Cartridge sub-assembly 181 has a cartridge 102 with barrel 103, drug volume 107 held by plunger 104 and septum 105.
Power source and indicator sub-assembly 183 has a biased means or spring 112 and indicator rod 111 held within casing 110a.
Needle and needle guard sub-assembly 182 has a casing 110b holding a needle shuttle 120 with needles 121 and 122. A needle guard 131 for preventing needle stick injuries is biased outwards by spring 132. Module 182 may be supplied sterilized. It also has a guard locking mechanism a shoulder 127 that retains the cartridge 102 in its correct position when inserted not shown.
Module 182 may contain a needle for subcutaneous, intramuscular or intra-dermal injections.
The assembled auto injector 184 is shown with an additional indicator cap and indicator knob 111a which is attached to the indicator rod 111 (not shown) and an additional front cap 141 which are optional features.
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A preferred embodiment of the present invention is a ready-to-use modular auto-injector that comprises
Another preferred embodiment of the present invention is a ready-to-use and re-usable modular auto-injector that comprises
Number | Date | Country | Kind |
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1902355.5 | Feb 2019 | GB | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/054704 | 2/21/2020 | WO | 00 |