A drug delivery device having a housing having an internal reservoir in communication with a drug delivery outlet via a fluid path. An expandable chamber disposed adjacent to the reservoir forces drug from the reservoir to the outlet when supplied with a gas. A flow regulating chamber, in communication with the fluid path, is capable of volumetric changes in response to temperature and/or pressure changes. An increase in the volume of the flow regulating chamber increases flow resistance to the outlet and thereby counteracts the corresponding increase in delivery rate resulting from the expansion of the expandable chamber due to the same volumetric changes in response to temperature and/or pressure. In a preferred embodiment, an electrical circuit has a current stabilizing element in electrical communication with an electrolytic cell which supplies the gas. A throttling device maintains a higher pressure in the device to reduce possible clogging of the fluid path. In a preferred embodiment, the drug delivery device is packaged to insulate the device from atmospheric pressure and humidity.
