Delivery device

A delivery device (600) comprising:

• a housing,
• a first variable volume cavity (610) containing a drive fluid,
• a flow restrictor (620) comprising a flow channel,
• a second variable volume cavity (631) in fluid communication with the first variable volume cavity through the flow channel,
• a variable volume drug reservoir (640) having in a situation of use an outlet means,
• the second variable volume cavity and the variable volume drug reservoir being arranged such that the volume of the drug reservoir diminishes when the volume of the second cavity increases,
• drive means (601) for expelling the drive fluid from the first to the second cavity through the flow restrictor, whereby drug is expelled from the drug reservoir through the outlet means,
• wherein venting means (652) is arranged between the first variable volume cavity and the flow restrictor.

A delivery device (600) comprising:

• a housing,
• a first variable volume cavity (610) containing a drive fluid,
• a flow restrictor (620) comprising a flow channel,
• a second variable volume cavity (631) in fluid communication with the first variable volume cavity through the flow channel,
• a variable volume drug reservoir (640) having in a situation of use an outlet means,
• the second variable volume cavity and the variable volume drug reservoir being arranged such that the volume of the drug reservoir diminishes when the volume of the second cavity increases,
• drive means (601) for expelling the drive fluid from the first to the second cavity through the flow restrictor, whereby drug is expelled from the drug reservoir through the outlet means,
• a fixed volume cavity (630) formed from a first material, the variable volume drug reservoir (640) being arranged there within and containing an initial amount of drug, the space between the drug reservoir and the fixed volume cavity forming the second variable volume cavity (631), the second variable volume cavity containing an initial amount of drive fluid,
• a compensation component (632) made from a second material arranged within the second variable volume cavity, wherein
• the volume of the compensation component is selected such that the combined thermal volume variation of the compensation component, the drive fluid and the drug contained within the fixed volume cavity essentially matches the thermal volume variation of the fixed volume cavity itself.

A delivery device (1, 600) comprising:

• a housing,
• a first variable volume cavity (31, 610) containing a drive fluid,
• a flow restrictor (50, 52, 430, 620) comprising a flow channel,
• a second variable volume cavity (19, 631) in fluid communication with the first variable volume cavity through the flow channel,
• a variable volume drug reservoir (40, 640) having in a situation of use an outlet means,
• the second variable volume cavity and the variable volume drug reservoir being arranged such that the volume of the drug reservoir diminishes when the volume of the second cavity increases,
• drive means (33, 601) for expelling the drive fluid from the first to the second cavity through the flow restrictor, whereby drug is expelled from the drug reservoir through the outlet means,
• wherein the housing comprises a transparent portion allowing the content of the second variable volume cavity or the flow restrictor to be viewed from outside the device, the drive fluid being coloured for easy visual verification of its presence in the second variable volume cavity or the flow restrictor.

A reservoir comprising:

• a cavity member defining a cavity (331) and having a first opening (332) and a second opening (333),
• a piston (311) having a distal end (312) facing towards the cavity, a proximal end (313) facing away from the cavity, a longitudinal axis and a circumferential outer surface portion (315), the cross-sectional area of the piston varying along the longitudinal axis thereof, the piston being received in the first opening and being moveable along the longitudinal axis,
• a seal member (350, 550) arranged between the cavity member and the piston, the seal member being adapted to seal the gap therebetween when the piston is moved along its longitudinal axis,
• whereby an area surrounded by the seal member corresponding to a cross-sectional area of the piston defines an effective piston area for transmitting a pressure to a fluid contained within the cavity.