A CARTRIDGE FOR A MEDICAL INJECTION DEVICE

摘要

The present invention concerns a cartridge (1) for a medical injection device having an injection needle (30) mounted thereon. The cartridge has a first variable volume reservoir (3) containing a liquid drug to be injected. Further the cartridge proximally comprises a movable plunger (4) and distally a septum unit (10). The septum unit comprises a first septum (11) being penetrable by a needle cannula, and a second septum (15). Further a one-way valve (20) is provided as a part of the septum unit. The one-way valve controls the flow from the first variable volume reservoir and into a second reservoir which is formed between the first septum and the second septum. The needle cannula penetrates into the second reservoir and the one-way valve allows liquid drug to flow from the first variable volume reservoir to the second reservoir only when a predetermined pressure is applied to the drug in the first variable volume reservoir.