What it is:compounding is making a patient-specific drug preparation that isn't commercially available as-is, whether that's a kid-friendly suspension, a preservative-free eye drop, or a chemo bag. Three USP general chapters govern how you're allowed to do it: <795>covers nonsterile compounds (capsules, creams, oral liquids), <797>covers anything that has to be sterile (IV admixtures, eye drops, injectables), and <800>layers on top of both whenever the drug itself is hazardous to the person making it.
The core problem:every compounding failure is really one of two failures. Either you introduced something that shouldn't be there (microbial contamination, the wrong concentration, a mixed-up label), or you exposed someone to something they shouldn't have touched (a hazardous drug with no barrier between it and your skin or lungs). Every rule in these chapters exists to close one of those two gaps.
What you do about it:match the preparation to its risk category, use the engineering controls and technique that category demands, assign a beyond-use date you can actually defend, and document it so the next person (or a board inspector) can reconstruct exactly what you did.
Sterile vs. nonsterile is a question about the final preparation, not about how "clean" the process feels.A capsule you fill by hand on an open bench can be perfectly fine under <795> because oral capsules don't need to be sterile. An eye drop made with the exact same care on that same open bench is a contamination risk, because anything placed directly on the eye (or injected, or inhaled into the lungs via a nebulizer in some cases) bypasses your normal barrier defenses. The route of administration decides which chapter you're under, before you've even picked up an ingredient.
Students usually meet these as three unrelated acronyms. They're actually one decision tree: figure out if the final product must be sterile, then figure out if any ingredient in it is hazardous. Both answers can be "yes" at once, which is exactly what happens every time a pharmacy compounds a chemo infusion.
Nonsterile compounding: oral liquids, capsules, topical creams and ointments, suppositories.
Sterile compounding: IV admixtures, injectables, ophthalmics, irrigations, anything entering a sterile body site.
Hazardous drug handling: worker protection layered on top of <795> or <797>, whichever applies.
<795> and <797> are about protecting the patient from the preparation. <800> is about protecting the worker from the drug.A nonsterile hazardous cream (say, compounded progesterone or a hormone cream) is under <795> for how you make it correctly, and under <800> for how you keep it off your own skin while you do. Those are two separate, stackable sets of rules, not competing ones.
Sterile compounding risk isn't a vibe, it's a structured judgment based on a few concrete variables: how many sterile containers and devices you're combining, how long the ingredients are exposed to air before the container is sealed, and whether you're starting from other sterile components or having to sterilize something yourself.
Sterile gloves protect the preparation from you. The primary engineering control (a laminar airflow workbench, biological safety cabinet, or compounding aseptic isolator) protects the preparation from the room. You need both, but if you had to lose one, losing the gloves is more survivable than losing unidirectional airflow, because room air is loaded with particles and skin flora that gloves alone can't fully stop from settling into an open vial.
The garbing sequence isn't arbitrary busywork, it's a deliberate progression from "dirtiest" to "cleanest," where each step is designed to not undo the step before it. This is the exact sequence tested on skills checks.
| I & II. Preparation and initial garb, dirtiest to cleanest | ||
| Step | What you do | Why it's in this order |
|---|---|---|
| Personal prep | Remove all jewelry (rings, watches, bracelets); confirm nails are short, clean, polish- and artificial-nail-free; check hands and forearms for cuts or irritation | Jewelry and long/polished nails harbor microbes that hand hygiene can't fully reach, and broken skin is a contamination and self-exposure risk before you've touched anything sterile |
| Shoe covers | Don without letting covered feet touch clean socks or the floor on the wrong side of the line | Floor and shoe soles are the most contaminated surfaces in the room; this step has to come before anything above the waist |
| Hair and beard cover | Fully contain all hair; beard cover if applicable | Shed hair and skin flakes are a major particle source, and they fall from the top down onto whatever you compound next |
| Face mask | Cover nose and mouth securely | Blocks respiratory droplets before you start the hand wash, since talking or breathing near an open hand wash sink can undo it |
| III & IV. Hand and arm wash, then gowning | ||
| Antimicrobial wash | Clean in strict order: fingertips → hands → wrists → forearms → elbows; rinse fingertips-downward | Washing fingertips-first and rinsing downward keeps water (and whatever it picked up) flowing away from the cleanest zone, not back across it |
| Dry | Lint-free towels only | Ordinary paper towels or cloth shed fibers that become airborne particles in a controlled environment |
| Gown | Don a clean gown without touching its outer surface; fasten completely at neck, waist, and cuffs | The outer surface is the barrier layer; touching it with bare or just-washed hands recontaminates the one surface meant to stay clean |
| V & VI. Hand sanitization, gloving, and cleanroom entry | ||
| Alcohol hand rub | Apply to hands after gowning, before gloving | The wash removed bulk soil; the alcohol step is the final microbial kill step immediately before the last sterile barrier goes on |
| Sterile gloves | Don without touching any non-sterile surface | One touch of a non-sterile surface after this point contaminates the glove and the whole point of the sequence is lost |
| Sterile glove alcohol | Apply sterile alcohol to gloved hands after donning, and re-apply routinely while working | Gloves aren't sterile forever; ongoing disinfection during long compounding sessions maintains the barrier |
| Final check | Confirm full PPE integrity, then perform a final glove sanitization at the anteroom line before entering the buffer area | The anteroom-to-buffer-room transition is the last checkpoint before you're working directly over sterile components |
The order is graded, not just the presence of each item.Donning a gown before a hair cover, or applying alcohol to gloved hands before actually donning sterile gloves, breaks the "dirty to clean" logic even if every item on the checklist eventually gets worn. If you can't state why a step comes where it does, you'll misorder it under exam pressure.
Once sterile gloves are on, touching your mask, adjusting your hair cover, or resting a hand on the outside of the hood frame contaminates that glove immediately. The fix isn't to keep working carefully, it's to re-sanitize or re-glove before touching anything sterile again. Aseptic technique has no partial credit in the moment it's broken.
Garbing correctly is necessary but not sufficient. USP <797> requires objective proof, at set intervals, that a specific person's aseptic technique doesn't introduce contamination, and that the compounding environment itself stays within its particle and microbial limits.
| Check | What it verifies | How it works |
|---|---|---|
| Gloved fingertip and thumb testing (GFT) | The individual compounder's aseptic technique, specifically hand contamination | The compounder presses gloved fingertips onto agar plates after garbing and after a simulated compounding session; the plates are incubated and read for colony growth |
| Media-fill testing | Whether a compounder's full process can introduce contamination into a sterile preparation | The compounder performs a mock compounding procedure using sterile growth media instead of actual drug, then the filled containers are incubated; any growth means the technique failed |
| Environmental monitoring | Whether the room and engineering controls (not the person) are maintaining their required air quality | Viable and nonviable particle sampling of the primary engineering control and the surrounding buffer/anteroom, done on a fixed schedule |
| Certification of engineering controls | Whether the hood, isolator, or cleanroom itself is functioning to spec | Performed by a qualified outside technician who checks airflow, particle counts, and physical integrity |
Technique degrades with complacency, and hoods drift out of calibration over time even without anyone doing anything wrong. Requalifying people and recertifying equipment on a schedule (rather than once at hire, or once at installation) is what actually catches the slow decline before a contaminated preparation reaches a patient.
Both pathways start the same way: is this preparation actually necessary (no commercially available product meets the patient's need), is it feasible, and is there a reliable formula or reference for it. From there the workflows diverge.
Inside a laminar flow hood, air comes off the HEPA filter in parallel, unidirectional streams. "First air" is the very first pass of that filtered stream to reach a critical site, before it's touched anything else. Reaching your hand, a syringe, or a vial into that stream between the filter and the critical site blocks first air from ever getting there and creates turbulence that can pull unfiltered room air in behind it. This is why technique inside the hood is about geometry (keeping critical sites downstream of the filter, unobstructed) as much as it is about cleanliness.
A beyond-use date is not an expiration date. Expiration dates come from manufacturer stability testing on a specific commercial product; a BUD is the compounding pharmacist's own conservative estimate of how long a preparation can be expected to remain safe and potent, and it's always calculated from when compounding began.
| USP <795> nonsterile default BUDs (used only when there's no stability data to support a longer date) | |
| Preparation type | Default BUD |
|---|---|
| Water-containing oral formulations | 14 days, stored under refrigeration |
| Water-containing topical, dermal, or mucosal-liquid formulations | 30 days |
| Non-aqueous formulations (and solid formulations made from a manufactured product) | Whichever is shorter: 6 months, or 25% of the time remaining until the active ingredient's own expiration date |
| USP <797> sterile compounding, general framework | |
| Category | Concept |
| Immediate-use | Low-complexity preparation administered within about 1 hour of starting; not held or stored, so a formal BUD doesn't apply the way it does to a batch |
| Category 1 (segregated compounding area) | Shorter default BUDs measured in hours, reflecting that it's made outside a full ISO-classified cleanroom suite |
| Category 2 (full cleanroom suite) | Longer default BUDs measured in days, because the ISO-classified environment and more extensive personnel qualification support a longer window; sterility testing can extend it further |
A patient asking "how long is this good for" about a compounded suspension needs the BUD you assigned at compounding, not the expiration date printed on the bulk API bottle you compounded it from. Those two dates answer different questions and mixing them up is a real dispensing error, not just a technicality.
Covers any compounded preparation that doesn't need to be sterile: capsules, oral suspensions and solutions, troches, suppositories, and topical or transdermal creams, gels, and ointments.
Governs any preparation intended to be sterile: IV admixtures, injectables, ophthalmic drops and ointments, and irrigations.
Applies whenever a drug on the NIOSH hazardous drug list is anywhere in the compounding process, whether the final preparation is sterile or not. The chapter's whole orientation is worker and environmental safety, not preparation quality.
The reasoning behind <800> is simple even though the rule list is long: hazardous drugs are hazardous because of what they do to fast-dividing or vulnerable cells, and the person compounding or administering them is exposed repeatedly, over a career, not just once.
| Exposure route | What creates the risk | What blocks it |
|---|---|---|
| Skin contact | Spills, splashes, or residue on vial exteriors and outer packaging | Chemotherapy-rated gowns, double chemo-tested gloves, and wiping down vials before they leave the containment area |
| Inhalation | Aerosolization from crushing tablets, opening capsules, or venting a syringe inside a non-closed system | Compounding inside a C-PEC, using a CSTD, and respiratory protection for powder-generating tasks |
| Needlestick / sharps | Direct percutaneous exposure during preparation or administration | Standard sharps precautions plus CSTD components designed to reduce needle manipulation |
| Surface contamination | Hazardous drug residue on countertops, IV poles, or floors that then transfers to bare skin | Dedicated hazardous drug workspace, routine deactivation/decontamination cleaning, and spill kits staged nearby |
A CSTD isn't just a fancier adapter, it's specifically engineered to prevent the transfer of environmental contaminants into the system and the escape of hazardous drug or vapor out of it. That's a two-way seal: it keeps the drug in and keeps outside air out, which is exactly why <800> requires CSTDs for both compounding and administration of antineoplastic hazardous drugs whenever the dosage form allows it.
| Parameter | When | Watching for |
|---|---|---|
| Gloved fingertip/thumb testing | Initial qualification, then at defined periodic intervals (more frequent for higher-risk category compounding) | Colony growth on agar indicating a break in personal aseptic technique |
| Media-fill testing | Initial qualification and periodic requalification | Growth in the mock preparation, meaning the compounder's full process (not just fingertips) can introduce contamination |
| Viable/nonviable air and surface sampling | Routine schedule set by the facility's SOPs, plus after any construction or equipment service near the compounding area | Particle counts or microbial colony counts exceeding the ISO classification limit for that space |
| PEC/SEC certification | At installation, after relocation or repair, and at a fixed recurring interval | Airflow velocity, HEPA filter integrity, and physical seal failures that would let unfiltered air reach the work zone |
| Hazardous drug surface wipe sampling | Periodically, per facility policy, in hazardous drug compounding and administration areas | Detectable hazardous drug residue on surfaces, signaling a containment or cleaning breakdown |