. . "As shown in FIG. 16C, upon filling the main fluid chamber 55 with the medicament or other substance to be contained therein, the flexible bladder and rear plug assembly are moved into the rigid vial such that the flexible flange 188 of the bladder is moved into engagement with the annular ridge 172, best seen in FIG. 9A, and the rear plug is pressed inwardly until the sealing tabs 226 are snapped" . .