FDA will limit the drug substances that can be compounded by 503A and 503B outsourcing facilities after being proposed for, but not yet approved for, its lists of bulk drug substances, the agency says in new guidance on the issue. 503A compounding pharmacies will be able to continue compounding most substances, including those that are the active ingredient in an FDA-approved drug, have a U.S. Pharmacopeia monograph, or are placed in FDA’s “Category 1” list of proposed bulk drugs that...