Vented Drug Reservoir Unit

Abstract

A reservoir unit (200) is provided comprising a housing (201) in which a reservoir (250) with a transparent portion (251) is arranged, the housing comprising a window (203) allowing a portion of the reservoir to be inspected. The reservoir unit is adapted to be moved from a first “cold” condition to a second “warm” condition with no visible water condensing on the interior surface of the window portion. Further, a vent (210, 211) is adapted to provide pressure equalization between the interior of the housing and the exterior. In this way it is possible to perform visual inspection of the reservoir at all times without being confused by dew or condensed water drops, e.g. when a prefilled reservoir unit containing a drug which requires storage at a given low temperature, as is the case for insulin-containing drugs, is taken out in ambient temperature.

Description

[0001]The present invention generally relates to a reservoir unit containing a fluid drug, the reservoir unit comprising means allowing a condition of the drug to be checked for, for example, but not restricted to, fibrillation of insulin.BACKGROUND OF THE INVENTION[0002]In the disclosure of the present invention reference is mostly made to the treatment of diabetes by injection or infusion of insulin, however, this is only an exemplary use of the present invention.[0003]Portable drug delivery devices for delivering a drug to a patient are well known and generally comprise a reservoir adapted to contain a liquid drug and having an outlet in fluid communication with a hollow infusion needle, as well as expelling means for expelling a drug out of the reservoir and through the skin of the subject via the hollow needle. The delivery device may be adapted for discrete use, i.e. injection of an amount of a drug a given number of times during the day, or they may be adapted for continuous ...

AI Technical Summary

Benefits of technology

[0010]Thus, in a first aspect a reservoir unit is provided comprising a housing defining an interior, the housing comprising a transparent window portion having an interior surface, and a vent allowing ambient air and aqueous vapour to pass between the interior of the housing and the exterior. A reservoir is arranged within the interior of the housing, the reservoir defining an interior adapted to contain a fluid drug, the reservoir comprising a transparent portion allowing a user to inspect at least a portion of the contained drug through the transparent window portion and the transparent reservoir portion. The reservoir unit is adapted to be moved from a first stable condition at 5° C. and 0-100% relative humidity (RH), to a second stable condition at 40° C. and 75-100% relative humidity, with no visible water condensing on the interior surface of the window portion. The reservoir unit should be able to be moved swiftly between the two conditions, e.g. within 5 or 10 seconds. Further, the vent is adapted to provide 80% pressure equalization between the interior of the housing and the exterior at a pressure differential of 350 mBar in less than e.g. 60 or 30 minutes in order to assure proper working of pressure sensitive components. In this way it is possible to perform visual inspection of the reservoir at all times (e.g. also when the reservoir unit has just been removed from a refrigerator) without being confused by dew or condensed water drops. Such a situation of use would be relevant for a prefilled reservoir unit containing a drug which requires storage at a given low temperature as is the case for e.g. insulin-containing drugs. As the user in most cases would inspect the reservoir shortly after the reservoir has been moved between the two conditions, e.g. after the unit has been taken out of a refrigerator, the reservoir unit may be adapted to prevent visible water condensing on the interior surface of the window portion within a predetermined period of time, e.g. 5, 10 or 30 minutes.

[0012]In accordance with different embodiments of the present invention, the prevention of visible water condensing on the interior surface of the window portion can be achieved in a number of ways, e.g. the entrance of water in the housing can be delayed or prevented, or water having entered the housing may be prevented from condensing on the window.

[0014]A reservoir unit in which the vent is adapted to prevent the entrance of aqueous vapour into the interior of the housing at a given aqueous pressure differential may for example comprise a valve controlled by the pressure differential between the interior of the housing and the exterior. In further embodiments the vent may comprise a molecular sieve in which water vapour will condense, or a capillary conduit adapted to condense aqueous vapour, the condensation of water blocking the conduit. The latter conduit may be combined with a heat sink as described above. To allow the vent to serve its pressure equalization purpose, the water condensed when the unit is moved from the first to the second stable condition should be allowed to evaporate within a relatively short time, e.g. in less than 30 minutes.

[0016]In case aqueous vapour has entered the interior of the housing (or is allowed to enter the housing), it may be prevented from condensing on the interior surface of the window. For example, at least a portion of the space between the window portion and the transparent reservoir portion may be sealed thus preventing aqueous vapour to enter and potentially condense. In a further embodiment the interior surface of the window portion may be provided with a coating preventing condensation of water or preventing the visible condensation of water. The latter may be achieved by a micro-porous coating absorbing and distributing water over the surface. In a further embodiment a heating element is provided preventing condensation of water on the window portion, preferably arranged in the vicinity of the window.

[0017]In the above disclosure a number of individual solutions to the problem of avoiding condensation of water have been disclosed, however, two or more of the individual solutions may be implemented in combination in order to achieve the desired object of venting the housing and at the same protecting the window portion from condensation of water. Indeed, the disclosed solutions may also serve to control water condensation inside the housing in general, e.g. it may be desirable to prevent water condensation on electronic components. In addition to controlling entrance of aqueous vapour, the above described vent will also prevent fluids (e.g. water) and dust from entering the interior.

Problems solved by technology

The first class comprises durable infusion pumps which are relatively expensive pumps intended for 3-4 years use, for which reason the initial cost for such a pump often is a barrier to this type of therapy.

Even weak degrees of fibrillation can be critical for a patient, as it can potentially cause allergy to insulin and change the time-profile for the insulin.

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