Compounding: Sterile and Non-Sterile Standards
The two legal tracks
A 503A pharmacy compounds for an identified patient based on a prescription or a prescriber's notation, uses bulk ingredients that appear on the FDA bulks list, and may not compound essentially a copy of a commercially available product. A 503B outsourcing facility compounds without patient-specific prescriptions, operates under cGMP, and reports adverse events; it is the only lawful route for anticipatory, office-use sterile batches at scale. Getting this framing right answers most compounding questions.
Standards of practice
Non-sterile compounding follows USP <795>; sterile compounding follows USP <797>; hazardous drug handling follows USP <800>. These govern facilities, environmental monitoring, personnel training and qualification, garb, cleaning, equipment verification, master formulation records, and beyond-use dating. Assigning a beyond-use date is not a guess: it is drawn from the applicable chapter's table using the type of preparation, the water content, the storage conditions, and whether the starting components were sterile. Sterile compounding additionally requires a designated clean area, ISO-classified environment, air and surface sampling, and documented competency for every compounder.
Traps
The most testable error is a pharmacy preparing sterile batches for office use without a patient-specific prescription - that is an outsourcing-facility function. The second is a beyond-use date longer than the standard allows for a water-containing preparation. The third is compounding from a bulk ingredient that is not on the bulks list.
Rule of thumb: sterile plus no patient-specific prescription equals 503B. Sterile plus patient-specific prescription equals 503A under <797>.