US Patent 10195345 Dedicated cartridge

A cartridge assembly for use with a drug delivery device is specified. The cartridge assembly comprises a cartridge with a retention cap and a cartridge holder. According to one aspect, the cartridge and the cartridge holder may be configured to be fixed to each other in a predetermined position According to another aspect, the retention cap comprises at least one coding feature configured to affix said cartridge to said cartridge holder in the predetermined position by the mating of said coding feature with a corresponding coding feature on the cartridge holder.