Aztreonam for injection (lyophilized): development of an automated solution batching process utilizing volumetric powder feeders.

As part of a commitment to fully automate the manufacture of a lyophilized dosage form of Azactam (Aztreonam for Injection), an automated solution batching procedure was developed. The lyophilization process requires solution batching of Aztreonam and L-arginine, the two constituents of the product. To avoid preblending of aztreonam and L-arginine prior to dissolution, a batching process was developed which makes use of two separate volumetric powder feeders. In conjunction with a feedback pH control system, these powder feeders provided for (a) a faster batching process, (b) a tight control of solution pH during batching, (c) a failsafe system to prevent operator error and equipment malfunction. Data are presented correlating bulk densities of various powders with feeder output along with solution pH profiles determined using the manual mode and the automated feedback pH control system.