The invention provides a
cartridge (1) for an
inhalation device for the generation and administration of a medically active liquid (2) in aerosolized form, the
cartridge comprising - a dimensionally stable outer casing (10), and - a collapsible inner tube (20) for holding the medically active liquid, being located inside the outer casing in the assembled state of the
cartridge, wherein the collapsible inner tube comprises an outlet end (21) having an outlet opening (22) and a closed end (23) opposite of the outlet end, the outlet opening and the (the center of the) closed end defining a main axis (X) of the inner tube connecting the outlet opening and closed end of the tube, wherein the closed end of the tube being closed by a welded seam (24) oriented transverse (preferably substantially perpendicular) to the main axis of the inner tube; and wherein the outer casing comprises a deformation element (11) contacting the welded seam (in the assembled state of the cartridge) such that the welded seam is deformed to a radially curved form by the contact between the welded seam and the deformation element.