A cartridge for use in a multi-compartment system, the cartridge including a housing having an opening at a top end, a sealing wall at a bottom end and wall openings through side walls of the housing; a displaceable sleeve sealingly mounted in the housing, the displaceable sleeve having a sealable filling opening at its top end, and an opening at its bottom end adapted and configured for sealing engagement with the sealing wall; the displaceable sleeve being axially displaceable between two positions along a longitudinal axis through the cartridge, a first position whereby the displaceable sleeve is in sealing engagement with the sealing wall and a seal is formed, and a second position where the sealing wall and the displaceable sleeve are disengaged, providing flow communication through the wall openings.