Glossary
Section 503A does not permit a pharmacy to compound a drug that is essentially a copy of a commercially available approved product, unless a prescriber determines and documents that the compounded version will produce a clinically significant difference for an individual patient. The restriction exists so that compounding remains a route for patients an approved product cannot serve, rather than a parallel manufacturing channel.
The FDA has been explicit that price is not such a difference, which is the point on which most of the compounded semaglutide question turned. The doctrine also complicates a bulk nomination for a substance that is already the active ingredient of an approved product: secretin is the case in this index where those two records meet.