In 1945, the U.S. Congress passed the Penicillin Amendment, modeled on the earlier Insulin Amendment. The former required batch certification of drugs wholly or partially composed of penicillin. Subsequent amendments extended the certification requirement to other antibiotics.

Later amendments extended this requirement to all antibiotics. In 1983 such control was found no longer needed and was abolished.

As a result, the regulatory scheme for antibiotics became different from that of other drugs (until essentially merged with the scheme for other drugs with the 1997 FDA Modernization Act). Antibiotics had to pass FDA’s batch certification program and be approved batch by batch.

They also had to adhere to drug monographs published by FDA, rather than, USP. This process was costly and time consuming for FDA and manufacturers.

It also made it redundant for USP to publish full monographs for antibiotics; instead, the USP included brief monographs that contained references to FDA’s standards.