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USP Chapters <795> and <797> Are Here: What Compounding Pharmacies and Prescribers Need to Know

Last year, we posted about the USP updates to its compounding chapters <795> and <797>, and the changes are officially in effect as of November 1, 2023. Because regulations can be a complex and tricky topic, we wanted to provide a brief overview to remind compounders and prescribers about these changes, with a focus on the beyond-use date (BUD) assignment and Category 3 CSPs.

Changes to BUD Assignment and Definitions 

Water activity

Because microbes require water to proliferate and because some drugs are susceptible to hydrolytic degradation, USP has added the concept of water activity (aw) to guide the assignment of a BUD, as follows: 

Non-preserved aqueous dosage forms (aw ≥ 0.60) = 14 days

Preserved aqueous dosage forms (aw ≥ 0.60) = 35 days

Oral liquids (non-aqueous) (aw < 0.60) = 90 days

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Other non-aqueous dosage forms (aw < 0.60) = 180 days


Any type of manipulation performed on conventionally-manufactured medications is classified as compounding, including the addition of components such as flavors. Because the compounds that are responsible for flavors contain reactive functional groups such as alcohols, ketones, and acids, they may react with other components in a formulation. Therefore, the USP has provided supplemental guidance for assigning a BUD to preparations involving adding a flavor.

Compounded Sterile Preparations (CSPs) Category Changes

In previous revisions, the USP defined CSPs depending on their “risk” into high-risk, medium-risk, low-risk, or low-risk with a 12-hour BUD. There are now four new categories: immediate-use and categories 1, 2, and 3. 

Immediate-Use CSPs

This category of CSPs should be used within four hours of the start of the preparation, and any remainder should be discarded. Importantly, if administration is not initiated within four hours of the start of preparation, the CSP should be discarded.

Category 1 CSPs

There have been no changes to Category 1 CSPs, which are assigned a BUD of ≤ 12 hours at room temperature or ≤ 24 hours when refrigerated.

Category 2 CSPs

The method for assigning a BUD to Category 2 CSPs is the most complex of all categories. Briefly, they can be assigned a BUD of > 12 hours at room temperature or > 24 hours when refrigerated. The BUD can also be extended by performing sterility tests and storing at lower temperatures, according to USP guidelines.

Category 3 CSPs

Due to the introduction of Category 3 CSPs, the USP has provided additional guidance on best practices when performing this type of compounding, including their BUD assignment, which may be “longer than established for Category 2 CSPs, up to 180 days,” as noted in the table below. 

These longer BUDs can only be assigned if the compounding site meets all the requirements as outlined in the revised USP chapter <797>, as we briefly outline below.

Garbing requirements

Because contaminants can be introduced into a sterile setting by almost anything, the USP has strengthened its guidance for garbing procedures. There is now a whole laundry list of requirements for anyone and anywhere sterile compounding is being performed, including:

  • No exposed skin in the buffer room (head-to-toe coverage)
  • Garbs should be low-lint and sterile 
  • Disposable garbing should not be reused.
  • Garbs must be re-sanitized after laundering.
  • Facility SOPs should describe its disinfection procedures. 

Aseptic Manipulation Competency

The USP now requires a work surface sample with a maximum of three colony-forming units (CFUs) before performing aseptic compounding and then again every three months for Category 3 compounding.

Environmental Monitoring and Sampling

In areas where Category 3 compounding will be performed, hood surface sampling and air sampling are required at least 30 days before Category 3 compounding will be started. Due to the use of ambiguous language previously (i.e., “periodically”), the USP has now specified weekly hood surface sampling at the end of each batch as well as monthly air sampling. 

Sterility testing is also required for assigning a BUD for Category 2 CSPs where sterility testing is required, such as for extending the BUD.

Additional Resources for Prescribers and Compounders

VLS Pharmacy & New Drug Loft are here to assist as the compounding pharmacy world adapts to these changes. This blog post is meant to provide a brief overview of changes to USP Chapters <795> and <797>, but it is not comprehensive. For specific questions, readers must refer to the official United States Pharmacopeia–National Formulary (USP–NF) text and can send inquiries to the USP directly at compoundingSL@USP.org. 

For more detailed general information about changes to BUD assignment and USP chapters <795> and <797>, please read the following resources:

Please comment below with any thoughts or questions. Reach out to our team to discuss updates to USP Chapters <795> and <797> or learn about best practices and partner with our experts. All medications from VLS Pharmacy and New Drug Loft are prepared in a lab that follows safety and quality standards per our status as a 503A pharmacy and in accordance with the latest USP guidance.



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