Final answer:
503A and 503B are categories of sterile compounding pharmacies regulated by the FDA. 503A pharmacies make medications for individual patients based on prescriptions, while 503B pharmacies produce medications in larger quantities without patient-specific prescriptions.
Step-by-step explanation:
503A and 503B are categories defined by the United States Food and Drug Administration (FDA) to regulate sterile compounding pharmacies. These categories distinguish between different types of pharmacies based on their activities and requirements.
503A pharmacies are traditional compounding pharmacies that make medications for individual patients based on specific prescriptions. They are regulated by individual state boards of pharmacy.
503B pharmacies, on the other hand, are large-scale outsourcing facilities that produce compounded medications in larger quantities without patient-specific prescriptions. They are regulated by the FDA under stricter guidelines.