A valved medicament delivery device including a housing having a chamber including coaxially aligned inlet and outlet, a medicament cartridge located within the chamber having a passage therethrough and membranes sealing the passage having a burst pressure of less than 10 atmospheres, a manually actuatable fluid delivery device having an outlet in fluid communication with the chamber and a manually actuated valve located between the outlet of the fluid delivery device and the chamber inlet for delivery of fluid under pressure to the valve. The medicament delivery device of this invention may be utilized to deliver a controlled unit dose of an medicament on demand by first pressurizing a pressure chamber in the pressure delivery device upstream of the valve, then opening the valve to open the membranes and express the medicament through the chamber outlet.