Abstract: The present invention concerns cartridges adapted to provide a solution for medical use such as a dyalysis solution by dissolving a plurality of substances in powder form in at least one liquid. The cartridge according to the invention comprises a container including a lateral wall, a bottom wall unitary with the lateral wall, the lateral and bottom walls delimiting a main volume, a central nucleus unitary with the bottom wall, the height of the central nucleus being substantially equal to that of the lateral wall to define an annular volume in the main volume, at least two separation walls imperviously unitary with the bottom wall, with the interior surface of the lateral wall and with the exterior surface of the central nucleus to delimit two secondary volumes in the annular volume, and at least two fluid connections adapted to connect the exterior of the container with the two secondary volumes.