Membrane shell of an implantable dosage system

A membrane shell (3) of an implantable dosage system, comprising a first half (1) and a second half (2), which both halves comprise an inner surface (5;

• 7) and an outer surface (4;
• 6), characterized in that the halves (1, 2) are adapted to be connected to each other through a closable joint comprising a closure edge (8) of the first half as continuous on the inner surface (5) of the first half essentially at its perimeter, and a closure edge (9) of the second half as continuous on the inner surface (7) of the second half essentially at its perimeter, and which closure edges (8, 9) of the halves comprise at least one groove (10) and/or at least one protrusion (11) as continuous or discontinuous, and which membrane shell (3) is adapted to be closed so that at least one protrusion (11) and/or at least one groove (10) of the second half becomes opposed to at least one groove (10) and/or at least one protrusion (11) of the first half through a snap-fit joint.