Device, kit, and method for filling a flexible reservoir container in a negative pressure chamber

A method for transferring a liquid medicament from a supply container to a flexible reservoir container, the method comprising:

• providing a fluid connection between the supply container and the flexible reservoir container;
• providing a separator arranged in the fluid connection for separating gas bubbles from the liquid;
• subjecting the flexible reservoir container to a reduced ambient pressure, thereby generating a negative pressure inside of the flexible reservoir container;
• sustaining normal ambient pressure inside of the supply container;
• subjecting the separator to the reduced ambient pressure, wherein the separation of the gas bubbles from the liquid in the separator is effected by the pressure difference between the liquid and the reduced ambient pressure;
• and
• conveying the liquid from the supply container to the flexible reservoir container, driven by the pressure difference between the inside of the supply container and the inside of the flexible reservoir container, wherein prior to filling the flexible reservoir container is evacuated via the separator, the separator being designed so that the flexible reservoir container is fluidly connected to its surroundings with its reduced ambient pressure as long as the separator has not yet come into contact with liquid.