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.

1 . A reservoir unit ( 100 ,  200 ,  300 ,  400 ) comprising:
 a housing defining an interior, the housing comprising a transparent window portion ( 103 ,  203 ,  303 ,  403 ) having an interior surface,   a vent ( 110 ,  211 ,  310 ,  411 ) allowing ambient air and aqueous vapour to pass between the interior of the housing and the exterior,   a reservoir ( 150 ,  250 ,  350 ,  450 ) 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,   wherein the reservoir unit is adapted to be moved from a first stable condition at 5° C. and 0-100% relative humidity, 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, and   wherein 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 60 minutes.   
   
   
       2 . A reservoir unit as defined in  claim 1 , wherein the vent ( 110 ,  211 ,  410 ,  411 ) is adapted to delay the entrance of aqueous vapour into the interior of the housing at a given aqueous pressure differential. 
   
   
       3 . A reservoir unit as defined in  claim 2 , wherein the vent comprises a membrane ( 110 ) restricting the passage of aqueous vapour into the interior of the housing. 
   
   
       4 . A reservoir unit as defined in  claim 2 , wherein the vent comprises a narrow conduit ( 211 ,  411 ) adapted to condense aqueous vapour. 
   
   
       5 . A reservoir unit as defined in  claim 4 , wherein the conduit comprises a condensing portion in the form of heat sink ( 260 ). 
   
   
       6 . A reservoir unit as defined in  claim 1 , wherein the vent ( 110 ) is adapted to prevent the entrance of aqueous vapour into the interior of the housing at a given aqueous pressure differential. 
   
   
       7 . A reservoir unit as defined in  claim 6 , wherein the vent comprises a valve ( 110 ) controlled by the pressure differential between the interior of the housing and the exterior. 
   
   
       8 . A reservoir unit as defined in  claim 6 , wherein the vent comprises a molecular sieve ( 110 ) in which water vapour will condense. 
   
   
       9 . A reservoir unit as defined in  claim 6 , wherein the vent comprises a capillary conduit ( 211 ) adapted to condense aqueous vapour, the condensation of water blocking the conduit. 
   
   
       10 . A reservoir unit as defined in  claim 8 , wherein the water condensed when the unit is moved from the first to the second stable condition will have evaporated within less than 30 minutes at the second condition. 
   
   
       11 . A reservoir unit as defined in  claim 1 , wherein aqueous vapour having entered the interior of the housing is prevented from condensing on the interior surface of the window. 
   
   
       12 . A reservoir unit as defined in  claim 11 , wherein at least a portion of the space between the window portion and the transparent reservoir portion is sealed ( 370 ). 
   
   
       13 . A reservoir unit as defined in  claim 11 , wherein the interior surface of the window portion is provided with a coating ( 480 ) preventing condensation of water or preventing the visible condensation of water. 
   
   
       14 . A reservoir unit as defined in  claim 11 , further comprising a heating element ( 490 ) preventing condensation of water on the interior surface of the window portion. 
   
   
       15 . A reservoir unit as defined in  claim 14 , wherein the heating element is arranged in the vicinity of the interior surface of the window portion. 
   
   
       16 . A reservoir unit as in  claim 1 , further comprising a fluid outlet ( 822 ) and an expelling assembly ( 800 ) adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the fluid outlet. 
   
   
       17 . A reservoir unit as in  claim 16 , further comprising:
 a transcutaneous device adapted to penetrate the skin of a subject, and   a mounting surface adapted for application to the skin of the subject,   wherein the expelling assembly, in a situation of use, is adapted for expelling drug out of the reservoir and through the skin of the subject via the transcutaneous device.   
   
   
       18 . A medical device, comprising a transcutaneous device unit ( 2 ) and a reservoir unit ( 5 ) as in  claim 16 , the transcutaneous device unit comprising:
 a transcutaneous device ( 30 ),   a mounting surface adapted for application to the skin of the subject, wherein the expelling assembly is adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the transcutaneous device,   wherein the transcutaneous device unit and the reservoir unit are adapted to be secured to each other in a situation of use.   
   
   
       19 . A pocket-sized reservoir unit ( 100 ) comprising:
 a housing defining an interior, the housing comprising a transparent window portion ( 103 ) having an interior surface,   a vent ( 110 ) allowing ambient air and aqueous vapour to pass between the interior of the housing and the exterior,   a reservoir ( 150 ) 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,   wherein the vent allows a flow of less than 7.5 litre per hour at a pressure differential of 500 mBar between the interior of the housing and the exterior.   
   
   
       20 . A reservoir unit as in  claim 19 , further comprising a fluid outlet ( 822 ) and an expelling assembly ( 800 ) adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the fluid outlet. 
   
   
       21 . A reservoir unit as in  claim 20 , further comprising:
 a transcutaneous device adapted to penetrate the skin of a subject, and   a mounting surface adapted for application to the skin of the subject,   wherein the expelling assembly, in a situation of use, is adapted for expelling drug out of the reservoir and through the skin of the subject via the transcutaneous device.   
   
   
       22 . A medical device, comprising a transcutaneous device unit ( 2 ) and a reservoir unit ( 5 ) as in  claim 20 , the transcutaneous device unit comprising:
 a transcutaneous device ( 30 ),   a mounting surface adapted for application to the skin of the subject, wherein the expelling assembly is adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the transcutaneous device,   wherein the transcutaneous device unit and the reservoir unit are adapted to be secured to each other in a situation of use.   
   
   
       23 . A reservoir unit as in  claim 19 , wherein the vent allows a flow of less than 5 l/h, or less than 2.5 l/h, at a pressure differential of 500 mBar between the interior of the housing and the exterior, and wherein the reservoir unit has a volume of less than 100 cm 2 , or less than 50 cm 2 . 
   
   
       24 . A reservoir unit as in any of  claim 1 , wherein the reservoir is prefilled with a fluid drug. 
   
   
       25 . A reservoir unit as in any of  claim 1 , wherein the reservoir is flexible and prefilled with a fluid drug.