Compliance
Resource Center
Everything you need to understand compounding pharmacy certification, USP standards, FDA inspection readiness, and quality systems — in one place.
Reference Guides
4 Guides503A vs 503B — A Plain-Language Comparison
503A pharmacies compound medications for individual patients pursuant to a prescription and operate primarily under their home state's Board of Pharmacy rules, aligned with USP guidance.
503B outsourcing facilities are FDA-registered and may compound in bulk without patient-specific prescriptions, but are held to current Good Manufacturing Practice (cGMP) standards — the same framework applied to pharmaceutical manufacturers.
Key differences at a glance:
- 503A requires a patient prescription; 503B does not
- 503A is regulated primarily by the state Board of Pharmacy; 503B by FDA
- 503A follows USP chapters 795, 797, 800+; 503B follows cGMP (21 CFR Parts 210 & 211)
- 503B audits are significantly more complex and time-intensive
- 503B facilities may sell to healthcare providers across state lines
The USP Chapters Every Compounding Pharmacy Should Know
The United States Pharmacopeia (USP) publishes binding and informational chapters that govern compounding practice. Your state's Board of Pharmacy determines which chapters apply to your facility.
- USP <795> — Non-sterile compounding standards
- USP <797> — Sterile compounding standards
- USP <800> — Hazardous drug handling requirements
- USP <1085> — Beyond-use dating of non-sterile preparations
- USP <1112> — Application of water activity to non-sterile preparations
- USP <1160> — Pharmaceutical calculations in prescription compounding
- USP <1163> — Quality assurance in pharmaceutical compounding
- USP <1176> — Prescription balances and volumetric apparatus
- USP <1207> — Package integrity evaluation — sterile products
- USP <1229> — Sterilization of compendial articles
What FDA Investigators Look for in a 503B Facility
FDA inspections of 503B outsourcing facilities focus on the same risk domains that define cGMP compliance for pharmaceutical manufacturers. Based on inspection data, the most frequently cited domains include:
- Environmental monitoring — sampling frequency, action levels, trending
- Documentation & records — accuracy, completeness, contemporaneous entries
- Training programs — evidence of current, role-specific training
- Change control — formal evaluation and approval of changes
- CAPA systems — root-cause identification and preventive action
- Equipment qualification — IQ/OQ/PQ documentation and periodic requalification
- Sterile production controls — aseptic technique, gowning, media fill performance
ACE's 503B audit is structured around these exact risk domains so that facilities can address gaps before FDA does.
Understanding cGMP for Outsourcing Facilities
Current Good Manufacturing Practices (cGMP) are the FDA's minimum quality standards for drug manufacturers. For 503B outsourcing facilities, adherence to cGMP is legally required — not optional.
The core cGMP framework for 503B is found in 21 CFR Parts 210 and 211, covering organization and personnel, buildings and facilities, equipment, control of components, production and process controls, laboratory controls, records and reports, and returned and salvaged drug products.
- cGMP regulations are significantly more rigorous than USP guidance
- Compliance is continuous — facilities must maintain cGMP at all times, not just during inspections
- A functioning Quality System is the backbone of all cGMP requirements
- Deviations must be formally investigated and documented with CAPA
- All batch records must be complete, accurate, and retrievable
Inspection Readiness Checklists
3 ChecklistsUse this checklist to assess your pharmacy's readiness before a State Board of Pharmacy inspection. Items are organized by the most commonly cited deficiency areas.
Use this checklist to assess your facility's readiness before an FDA inspection. Items reflect the most commonly observed cGMP deficiency areas in 503B facilities.
Environmental monitoring failures are among the most frequently cited deficiencies in both 503A and 503B inspections. Use this self-assessment to evaluate your EM program.
Compounding Compliance Glossary
16 TermsFDA's minimum quality standards for drug manufacturing. Required for all 503B outsourcing facilities and pharmaceutical manufacturers. Governed by 21 CFR Parts 210 & 211.
A scientific nonprofit organization that sets quality standards for medicines, food ingredients, and dietary supplements. USP chapters (e.g., <795>, <797>, <800>) govern 503A compounding practice.
A licensed pharmacy that compounds medications for individual patients pursuant to a valid prescription. Regulated primarily by the state Board of Pharmacy.
An FDA-registered facility that compounds drug products in bulk for healthcare providers without patient-specific prescriptions. Subject to cGMP requirements and FDA inspection.
A quality system process that identifies the root cause of an issue, implements a correction, and takes preventive action to stop recurrence. A core cGMP requirement for 503B facilities.
A document issued by FDA investigators at the conclusion of an inspection, listing observations of practices that may violate the Food, Drug, and Cosmetic Act. Does not constitute a final FDA determination.
A systematic program to assess microbial and particulate contamination in cleanroom environments. Includes air, surface, and personnel sampling at defined frequencies and locations.
A written, step-by-step document describing how a specific task or process should be performed. SOPs must be current, accessible, and followed by all applicable personnel.
The state-level regulatory body that licenses and oversees compounding pharmacies (503A). Rules vary by state. ACE auditors review your specific state's BoP requirements before conducting an assessment.
The date after which a compounded preparation should not be used. Assigned per USP <795> (non-sterile) or <797> (sterile) requirements based on formulation, container, and storage conditions.
Installation Qualification, Operational Qualification, and Performance Qualification — the three-phase process for validating that equipment is installed, operates, and performs as intended.
A test result that falls outside the established acceptance criteria. OOS results must be investigated using a formal, documented process before a product disposition decision is made.
The biologically active component of a compounded drug product. APIs must be sourced from qualified suppliers with Certificates of Analysis reviewed against established specifications.
A document from a supplier certifying the quality, purity, and composition of a raw material. COAs must be reviewed and retained for all incoming ingredients.
The department or individual(s) responsible for quality oversight in a 503B facility. The QU must be independent of production and have final authority on product release, batch approval, and SOP sign-off.
Highly purified water used in the production of sterile drug products. WFI systems must be validated, routinely monitored, and meet USP <1231> and cGMP requirements.
Official Regulatory Resources
8 LinksIndustry Context
Why This MattersThe data is clear: the vast majority of 503B outsourcing facilities are receiving observations during FDA inspections — and the trend is worsening. The most common root causes are not exotic regulatory failures; they are documentation gaps, untrained personnel, and quality systems that exist on paper but are not consistently followed in practice.
ACE certification is designed specifically to find these issues before an FDA investigator does. Facilities that have completed the ACE process enter inspections with a documented quality posture — and a remediation track record to show for it. View our certification programs →
Put This Knowledge to Work
With an ACE Certification
Our team of Pharm.D. professionals can assess your facility against every standard listed on this page — and help you close the gaps before a regulator finds them.