An add-on for a self-injector including an adaptor and a bent fluid path is provided. The adaptor includes at least one coupling sized and shaped to couple the adaptor to a fluid reservoir. The bent fluid path is configured at a first end to penetrate tissue and coupled at a second end to the adaptor. The add-on coupled to the fluid reservoir forms an integral self-injector cartridge unit configured to be sterilized and filled with an injectable. The adaptor is configured to couple to a self-injector at least one of a plurality of reservoirs having different sizes and tip types.