As shown typically in FIGS. 19 and 20, when fully expanded, the flexible bladder 354 conformably engages the inner wall of the rigid vial to thereby eliminate any ullage or dead space and allow all of the medicament or other substance contained with the main fluid chamber 355 to be dispensed therefrom. [0102] As described above, the flexible bladder 538 is preferably made of a relatively low perme