The invention relates to a needle magazine for storing and dispensing a plurality of needle assemblies for use on an injection device.
Medical injection devices are used to deliver selected doses of medication to patients. Some medication, such as insulin is self-administered. The typical diabetes patient will require injections of insulin several times during the course of the day. In order to prevent infections it is recommended to use a sterile needle assembly for each injection. Needle assemblies are often delivered in magazines where each magazine contains only one needle assembly in a sterile compartment. Such a magazine is described in U.S. Pat. No. 5,971,966. Using a needle assembly of this kind requires the patient to open the magazine and to fasten the needle assembly on to the injection device prior to each injection. The storage of sterile needle assemblies of this type and the final disposable of used needle assemblies present a problem, since new sterile needle assemblies are often carried loosely in purses or briefcases, and used needle assemblies are often disposed of unsafely.
To overcome these problems a needle magazine for storage and dispensing a plurality of needle assemblies has been developed. This prior art magazine is shown in U.S. Pat. No. 5,829,589 and is made up from a container having a plurality of confinements each containing a needle assembly. A cover is rotatably mounted on top of the container. When aligning a slot in the cover with the confinement, the user can access the confinement. The needle assembly is connected to the injection device by forcing the tip of the injection device into the confinement where the needle assembly is force fit, e.g. by a well-known luer-coupling, onto the tip of the injection device. The needle assembly can then be detached from the magazine. When the used needle is to be placed in the magazine the user has to conduct the same procedure again.
The prior art magazine is attached to the injection device by fitting the entire magazine into an open end of the removable cap of a pencil-shaped injection device. Due to the dimensions of a pencil-shaped injection device only five needle assemblies can be contained in the magazine. An ordinary disposable injection device usually contains 300 IU of insulin. For many diabetes patients this is sufficient for 10 to 20 injections, therefore one magazine of needle assemblies are not enough for the lifetime of one disposable injection device, which is very inconvenient.
For sight-impaired people it is difficult to see the location of the slot in the cover into which the tip of the injection device has to be placed, making the person holding the magazine vulnerable to accidental needle-stick injuries.
It is also somewhat difficult to use the prior art magazine since it requires the ability to push forward the injection device and to rotate it. This is especially difficult for elderly people with limited strength and reduced mobility of the hands. In general it is difficult for most people to handle the small needles of the prior art magazine.
It is an object of the present invention to provide a needle magazine for storing and dispensing a plurality of needle assemblies by which a great number of needle assemblies can be contained in the magazine and which magazine overcomes the inconveniences of the prior art magazines.
It is further an object of the present invention to provide a needle magazine for storing and dispensing a plurality of needle assemblies, and by which there are no or only limited risk of accidental needle-stick injuries.
Finally it is the object of the present invention to provide a needle magazine where the needle assemblies can be positioned onto the injection device in a simple and easy manner making it suitable for sight-impaired people and for people with only limited physical strength or motoricity.
This is obtained by a needle magazine for storing and dispensing a plurality of needle assemblies for use on an injection device having a housing accommodating a cartridge containing medicine for a number of dosed injections and which needle magazine can be carried on the injection device, which needle magazine comprises;
a plurality of confinements each containing a needle assembly having a first distal end, which is sharpened for piercing the skin of the user and an opposite proximal end and a side wall there between, which confinements each has a first distal surface and an opposite proximal surface,
a shell connecting the confinements side by side, and
means for supporting each needle assembly in an upright position, having the first distal end pointing towards the first distal surface and the opposite proximal end pointing towards the opposite proximal surface,
Which needle magazine according to the invention is Characterized in that
the shell can be rotated in order to index the needle assemblies and to position one of the needle assemblies above the cartridge, and that
the shell can be activated for bringing the proximal end of the positioned needle assembly into contact with the cartridge, and the distal end of the needle assembly into a position where the distal end of the needle assembly is located outside the magazine, whereby the medicine can be injected.
The needle assemblies in the needle magazine are confined in separate, sterile confinements. These confinements are connected in a side-by-side relation. In use one needle assembly is positioned above the cartridge containing the medicine to be expelled. When activating the shell, the shell impacts the hub of the needle assembly while the distal end of the needle unit passes through the distal surface of the confinement. At the same time the proximal end of the needle is forced to pass through the proximal surface of the confinement and further into the cartridge, where it pierces the elastomeric seal.
After the injection is done the shell is brought back to the original position and can be rotated which brings the next needle assembly in position above the cartridge.
The magazine can either be a loose part, which is connected to the injection device; in this case the entire magazine is disposed off when all the needle assemblies in the magazine are used. The magazine however could also be made as an integral part of the injection device, is this case the injection device including the needle magazine is disposed off when all the needle assemblies in the magazine is used, or when all the medicine contained in the cartridge is used.
When, as disclosed in claim 2, the shell connecting the confinement can be shifted between a first position where the needle assembly is fully confined inside the confinement and a second position in which the positioned needle assembly penetrates the distal surface and the proximal surface, it is ensured that the sterile barrier is penetrated.
When, as disclosed in claim 3, the shell is shifted between the first position and the second position by moving the shell towards the injection device, it is ensured that the magazine can be operated in a simple manner.
When, as disclosed in claim 4, the magazine has means locking the shell in the second position against the force of a spring, and that the means can be released whereby the shell travels back into the first position under influence of the spring, it is ensured that the shell in an easy way can be shifted between the parked position and the injection position.
When, as disclosed in claim 5, the means supporting the needle assemblies in an upright position is either connected to a hub located on the side wall of each needle assembly inside the confinement or supporting the hub from outside the confinement, it is ensured that the needle assemblies are held in the correct upright position at all times. The means can either be a number of arms provided on the shell as disclosed in claim 6, which arms is made up from several parts connected together through a number of film-hinges allowing the arm to flex as disclosed in claim 7, or the means for supporting the needle assemblies could, as disclosed in claim 8, be a number of circular walls projecting from the shell
When, as disclosed in claim 9 the confinements is a plurality of cavities each having the form of a circular segment, which segments together forms a full circle, it is ensured that shell has a circular appearance. Each circular segment must be able to fit over the cartridge, when the shell is pushed backward against the injection device prior to an injection.
When, as disclosed in claim 10 each confinement is a bag, and that a plurality of such bags each containing one needle assembly is connected together. Instead of dividing the shell into circular segments, the needle assemblies can be provided packed in sterile bags. These bags are preferably connected together to form a string.
When, as disclosed in claim 11 the magazine has means preventing the shell from being rotated in one rotational direction, it is ensured that the shell cannot be rotated backwards in order to reuse the needle assemblies. The means preferably being a number of pawls located on the housing of the magazine and which pawls engage a pawl wheel, preferably a star-shaped pawl wheel, on the interior surface of the shell.
When, as disclosed in claim 12 the magazine has means preventing the shell from rotating more than approximately 360 degrees, it is ensured that the shell is limited to one full rotation, thereby preventing reuse of the needle assemblies once the content of the magazine is used once.