Drug delivery devices are provided having a needle assembly portion and a drug device portion, where the needle assembly portion is removably coupleable to the drug device portion. In some embodiments, the needle of the needle assembly may be moveable between a retracted position and an extended position for piercing into a subjects skin.

An active ingredient cartridge (2) for a medical syringe (1) with an essentially cylindrical hollow body (16) made of a first plastic material that can be filled with an active ingredient is intended to facilitate filling of the active ingredient and also to enable high throughput rates during filling in automated processes. For this purpose, according to the invention, the hollow body (16) is provided at one end (4) with an integrated closure body (50) made of a second plastic material which is softer than the first, wherein the hybrid body formed by the hollow body (16) and the closure body (50) is obtained by a 2K injection molding process.