503A vs 503B (pharmacy compounding)
Compounded vs FDA-approved, 503A vs 503B, and the accreditation programs that distinguish them.
Definition
Two FDA categories for sterile compounding pharmacies. 503A: state-licensed pharmacies that compound patient-specific prescriptions (must hold a valid prescription with a named patient). 503B: voluntarily-registered outsourcing facilities that can compound in bulk without prescriptions, must comply with full Current Good Manufacturing Practice (cGMP) standards.
Definition curated by Weight Loss Rankings — sourced from FDA labels and peer-reviewed PubMed literature, never AI-generated summaries.
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