RESERVOIR FOR AN INHALATION DEVICE

The invention relates to the field of inhalation devices for medically active liquids. In particular, the invention relates to a cartridge containing said liquid for such an inhalation devices. A cartridge (1) for the storage of a medically active liquid (L) and for supply of the same to a pumping unit of an inhalation device comprises an outer container (3) enclosing a collapsible inner bag (4), and a cap (5) which is capable of closing the container (3), the cap (5) further providing an openable access opening (6) to the inner bag (4), wherein further, the container (3) of the cartridge (1) has a pressure compensation opening (7), and wherein said pressure compensation opening (7) is located in a region (8) which is covered by the cap (5). In a method for providing a pressure compensation to the collapsible inner bag-containing interior of the outer container (3) of a cartridge (1), initially, before the cartridge (1) is connected to a holder (2), the pressure compensation opening (7) is closed, and subsequently, when the cartridge (1) is connected to the holder (2), by way of mechanically deforming (i) a pressure compensation opening comprising region of the outer container (3) and/or (ii) a compensation opening covering region of the cap (5), an air gap (9) is provided which allows for a pressure equalization of the bag-containing interior with the ambient pressure.