USP 797 & Bacteriostatic Water — What Compounding Pharmacies Need to Know

USP <797> (Pharmaceutical Compounding — Sterile Preparations) is the primary standard governing sterile compounding in the United States. For pharmacies that use bacteriostatic water as a component in compounded sterile preparations (CSPs), USP <797> has specific implications for ingredient quality, documentation, and beyond-use dating.

USP 797 Ingredient Requirements

USP <797> requires that all ingredients used in CSPs be of pharmaceutical grade, obtained from licensed suppliers, and accompanied by documentation that confirms their quality. For bacteriostatic water, this means your supplier must provide a Certificate of Analysis that includes: HPLC benzyl alcohol assay (actual measured concentration), endotoxin test results (EU/mL), sterility confirmation, pH measurement, lot number, manufacturing date, and expiration date.

Documentation Checklist for USP 797 Compliance

Required Documentation	Renew Lab Group Provides
HPLC Benzyl Alcohol Assay	✅ Lot-specific % value on COA
Endotoxin Test (LAL)	✅ EU/mL result on COA
Sterility Confirmation	✅ Per USP <71> on COA
pH Measurement	✅ Measured value on COA
Lot Number & Expiration	✅ On label and COA
Supplier Information	✅ Manufacturer details on COA

Beyond-Use Dating Under USP 797

When bacteriostatic water is used to reconstitute a compound, its 0.9% benzyl alcohol preservative supports longer beyond-use dates for multi-use preparations compared to sterile water. Under USP <797>, the compounder assigns a BUD based on available stability data and storage conditions. The preservative activity of bacteriostatic water is a supporting factor in extended BUD assignments.

Related: What Is Beyond-Use Dating? | Certificate of Analysis | Pharmacy Wholesale Account