The USP <797> cleaning requirements are among the most frequently cited issues in inspections of pharmacies and facilities that prepare compounded sterile preparations (CSPs): minimum frequencies not met, the wrong agents used inside the hood, no evidence of contact times. The revision of USP General Chapter <797> — published on November 1, 2022 and official since November 1, 2023 — made these requirements far more explicit: a table of minimum frequencies by surface, three agent types with distinct roles, and precise rules on what may enter the ISO 5 zone. This article covers the frequencies, the required agents and the mistakes to avoid, with a comparative look that is useful for anyone working under EU GMP.
USP <797> cleaning requirements: what the revised chapter establishes
USP <797> Pharmaceutical Compounding — Sterile Preparations governs sterile compounding in the United States and dedicates a specific section to "Cleaning, Disinfecting, and Applying Sporicidal Disinfectants and Sterile 70% IPA". The framework works on three levels, each with a different purpose:
- cleaning agent: physically removes residues, soil and contamination from a surface, with no claim of microbicidal activity;
- EPA-registered disinfectant (or an equivalent outside the US): destroys bacteria, fungi and viruses on inanimate surfaces, after cleaning;
- sporicidal disinfectant: also destroys bacterial and fungal spores, and must be applied at least monthly to the designated surfaces.
Added to these is sterile 70% isopropyl alcohol (sIPA), which the chapter treats as a supporting sanitizer — for gloves, items entering the hood and critical surfaces — not as a substitute for the cleaning + disinfection pair. An EPA-registered "one-step" cleaner-disinfectant may cover cleaning and disinfection in a single pass, but it never removes the obligation of periodic sporicidal application.
The minimum frequencies of Table 10
The operational core of the section is the table of minimum cleaning and disinfecting frequencies (Table 10 of the revised chapter), covering classified areas and the perimeter of the Segregated Compounding Area (SCA). Here is the summary for Category 1 and 2 preparations:
| Surface | Cleaning and disinfecting | Sporicidal application |
|---|---|---|
| PEC and equipment inside it | Every compounding day (and whenever contamination is known or suspected) | Monthly |
| Removable work tray of the PEC | Work surface daily; all surfaces and the area underneath monthly | Monthly (including the underside and the area beneath) |
| Pass-through chambers | Every compounding day | Monthly |
| Work surfaces outside the PEC | Every compounding day | Monthly |
| Floors | Every compounding day | Monthly |
| Walls, doors and door frames | Monthly | Monthly |
| Ceilings | Monthly (in the SCA only when visibly soiled or when contamination is suspected) | Monthly (same exception for the SCA) |
| Storage shelving and bins | Monthly | Monthly |
| Equipment outside the PEC | Monthly | Monthly |
Two important clarifications. First: for Category 3 preparations (those with extended beyond-use dates) the sporicidal frequency moves from monthly to weekly for the PEC, pass-throughs, work surfaces and floors. Second: these are minimum frequencies — internal SOPs must raise them whenever the facility's risk assessment requires it, and cleaning must in any case be repeated after every spill and whenever contamination is known or suspected.
Frequencies, agents and official interpretations of USP chapters change more often than you might think. For a weekly, practical, no-fluff update on these topics, subscribe to The Pragmatic GMP, GuideGxP's free newsletter: the fastest way not to be caught off guard by the next revision.
The right agents in the right place: sterility, low-lint wipers and contact times
Beyond the "when", USP <797> is precise about the "with what". Four rules generate most non-conformities:
- Only sterile agents inside the PEC. Cleaning agents, disinfectants and sporicidal agents used inside the primary engineering control (laminar airflow workbench, isolator, BSC) must be sterile; outside the PEC, sterile agents are recommended. Cleaning supplies used in the PEC must also be sterile, with the exception of tool handles and holders, which must still be cleaned and disinfected before use.
- Low-lint materials. All cleaning supplies must be low-lint; disposable wipers, sponges and mop heads are recommended.
- Documented contact times. Follow the manufacturer's directions or published data: the same product may require, for example, 1 minute as a bactericide and 3 minutes as a sporicide. Applying the sporicidal agent and wiping it dry immediately is one of the most frequent mistakes.
- sIPA used for what it is. Sterile 70% isopropyl alcohol must be applied to gloves immediately before compounding and regularly during the work, and to every item entering the PEC (allowing it to dry). It is not a cleaner and does not replace the scheduled disinfection.
USP <797> and EU Annex 1: two worlds, one shared logic
For professionals working under EU GMP, the USP chapter is a useful benchmark. EudraLex Annex 1 (rev. 2022), which applies to industrial sterile manufacturing, follows the same logic: a documented cleaning and disinfection programme, use of more than one disinfecting agent, periodic application of a sporicidal agent, sterile disinfectants in Grade A and B zones, and demonstrated efficacy of the agents. The differences lie in scope — Annex 1 covers the manufacture of sterile medicinal products, USP <797> covers the compounding of CSPs — and in prescriptiveness: the USP table of minimum frequencies by surface is more granular than what Annex 1 explicitly requires, which is exactly why it is an excellent benchmark for anyone writing cleanroom cleaning SOPs in Europe.
The most common mistakes found in inspections
- Sporicidal agent forgotten or undocumented: daily disinfection is in place, but there is no evidence of the monthly application (or weekly for Category 3).
- Non-sterile agents in the PEC: "ward-grade" bottles used inside the hood, or non-sterile IPA.
- Ignored contact times: surfaces dried before the agent has acted, with no reference to contact time in the SOPs.
- Incomplete logs: minimum frequencies can only be demonstrated with signed, dated records per surface, not with a generic "cleaning done".
- Misunderstood one-step products: a cleaner-disinfectant used as an alibi to skip the periodic sporicidal application.
GuideGxP recommendation
Turn Table 10 into a surface-by-surface cleaning programme with three columns: agent (and its sterility), minimum frequency and contact time. Link each row to a signable log and have the programme verified during self-inspections, sampling the previous month's records. If your facility compounds in Category 3, highlight in your SOPs the surfaces that move to weekly sporicidal application: it is the first thing inspectors check. And remember that the USP frequencies are the floor, not the ceiling: the local risk assessment can only raise them.
If you work under EU GMP and want to master contamination, sterility and validation with the same operational approach, our Operational Guide to GMP Annexes 1, 15, 16 and 20 covers the Contamination Control Strategy, cleanroom disinfection and the qualifications required by Annex 1, with ready-to-use toolkits.
