Abstract: A hypodermic injection device including an injector and a medicament and needle ampule wherein the needle is initially isolated from a possibly corrosive medicament, but wherein the needle is movable to a position in flow communication with the medicament only at the moment of injection, and an injector device into which the ampule can be loaded under controlled conditions of needle entry force and depth, medicament entry into tissue being accomplished while the needle is moving in its penetration of tissue.

Abstract: A self-contained predetermined dosage hypodermic ampule with enclosed sterile needle projected by a companion injector device from the sealed forward end of the ampule, with liquid medicament pressurizing means for dispensing the medicament from the needle and into the tissue of the patient during penetration of the tissue by the needle, all portions of the length of the needle being hygienically sealed from external contamination at all times; the companion injector means having simply operated and dependable safeguards against accidental operation, and the injector means and hypodermic needle cooperating to insure smooth, non-sticking operation of the medicament pressurizing means.