An apparatus for transdermal injection includes a sleeve including a proximal end, a distal end, and an inner wall surface extending along the sleeve from a first opening at the proximal end to a second opening at the distal end. The inner wall surface forms a channel in the sleeve, the channel having a first portion with a substantially frustoconical shape. The channel of the sleeve is configured to receive a substantially frustconically shaped injection cartridge, to substantially uniformly support the injection cartridge during a transdermal injection operation, and to prevent movement of the injection cartridge out of the distal end of the sleeve.
