Drug cartridge, drug delivery device, and methods for preparing thereof

A drug delivery device comprising:

• a body having a plurality of fluid ducts and at least one outlet duct formed therein;
• and,
• a plurality of drug cartridges attached to the body, the drug cartridges each including a reservoir for accommodating at least one drug,
• wherein, a first of the drug cartridges includes a fluid outlet,
• wherein, a first of the fluid ducts, is aligned to extend from the fluid outlet,
• wherein, an adjustable seal, formed by a sealing sheet joined to a sealing surface, selectively seals the fluid outlet, the seal being adjustable from a first state, where the fluid outlet is sealed, to a second state, where the fluid outlet is not sealed,
• wherein the sealing sheet is secured to a shiftable sealing element, and, wherein displacement of the shiftable sealing element causes delamination of the sealing sheet from the sealing surface and results in adjustment of the seal from the first state to the second state.