Swab and Rinse Acceptance Limit Calculator
Swab and rinse limits from the MACO, corrected for recovery, with the LOQ check.
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- Free preview: the method, the limits that apply and the verdict for your input, with the first rows of a list; computed figures stay hidden until the pass.
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Acceptance limits
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About the Swab and Rinse Acceptance Limit Calculator
Turns the MACO of a product changeover — or a surface limit you already have — into the acceptance limits a cleaning validation protocol needs: the residue allowed per cm², per swab of 25 or 100 cm², per mL of the solvent the swab is extracted into, and per mL of the final rinse. Each limit is corrected for the recovery of the sampling method, and the method's LOQ is checked against it, using the equations and rules of the APIC cleaning validation guidance and the cleaning validation section of EU GMP Annex 15.
Paste your swab results, and a rinse result if you have one, to see each location against the limit, results below the LOQ counted at the LOQ, and the carry-over of the whole train estimated against the MACO. Without a pass it shows a free preview: the method, the rules that apply and the verdicts, with every computed limit and figure hidden; the figures, the working and the PDF, Excel and Print exports unlock with a Premium pass.
How to use it
- Start from the MACO and the shared product-contact surface of the train, or from a surface limit.
- For swabs, choose the area of one swab, then enter the recovery from your recovery study and the volume the swab is extracted into.
- For a rinse, enter its volume, whether it reaches the whole shared surface or part of it, and the rinse recovery.
- Enter the LOQ of the analytical method to check that it can show the limits are met.
- Optionally open Check results and paste one swab result per line. Without a pass the report stays a free preview with its figures hidden; the PDF, Excel and Print unlock with a Premium pass.
Examples
MACO 50 mg · shared surface 25,000 cm² · 25 cm² swabs · recovery 80 % · 10 mL extraction · rinse 20 L, recovery 90 % · LOQ 1 µg/mL
Surface limit 2.000 µg/cm² · 50.00 µg per swab · 40.00 µg as found · 4.000 µg/mL in the extract · rinse 2.500 µg/mL, 2.250 µg/mL as found · LOQ 25 % and 44 % of the limits
Discharge chute: 4.4 µg/mL in 10 mL, blank 0.05 µg/mL
(44 − 0.5) µg ÷ 0.8 = 54.4 µg on 25 cm² = 2.18 µg/cm², above the 2 µg/cm² limit
Common uses
- Writing the acceptance criteria of a cleaning validation protocol from the MACO.
- Checking that an analytical method’s LOQ is low enough for the swab and rinse limits.
- Evaluating the swab and rinse results of a cleaning run against the limits.
- Comparing 25 cm² and 100 cm² swabs, or different extraction volumes, before a study.
The equations
From the APIC guidance on aspects of cleaning validation in active pharmaceutical ingredient plants:
- Surface limit = MACO ÷ total shared product-contact surface (equation 4.2.5-I). Per swab, multiply it by the area swabbed.
- Rinse limit = MACO ÷ volume of the rinse, for a rinse that reaches every shared surface; for part of the train, the surface limit times the area the rinse reaches.
- Recovery: the amount found is divided by the recovery (equation 4: M = Mres ÷ R). The tool also shows the limit "as found" — the limit times the recovery — which is what the analysis returns when the residue is exactly at the limit, and the concentration in the swab extract at that point.
- Carry-over from the swabs: total surface × the mean residue per cm² of the swabs, corrected for recovery (equation 6); from a rinse, the rinse volume × (concentration − blank) (equation 5).
Recovery and LOQ rules
- Recovery (APIC 8.2.4): 90 % or more is usually acceptable and need not be taken into account; below 90 % it must be included in the calculation; below 50 % it should not be used. The tool applies the correction at 90 % or more too unless you switch that off.
- LOQ (APIC 8.2.3): about half of the acceptance limit or lower, and never higher than the limit. A result below the LOQ is reported as the LOQ, the worst case.
- EU GMP Annex 15, section 10: carry-over limits are based on a toxicological evaluation, acceptance criteria consider the cumulative effect of the items in the equipment train, the protocol names the sampling locations, and recovery must be shown from every product-contact material with every sampling method used.
Sources
- APIC (Cefic) publications — Guidance on aspects of cleaning validation in active pharmaceutical ingredient plants
- EU GMP, EudraLex Volume 4 — Annex 15, Qualification and validation, section 10 (cleaning validation)
Limitations
- The MACO itself — from a health-based exposure limit, a dose criterion or a 10 ppm criterion — is an input: work it out in your cleaning risk assessment first.
- A rinse limit assumes the rinse wets every surface it is credited with; prove that during equipment qualification.
- The LOQ is taken in µg/mL of the solution analysed, the same for the swab extract and the rinse.
- Your validated recovery and LOQ, measured on the same surface material and finish, decide; the tool does the arithmetic.
- Up to 200 swab results at a time.
Privacy
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Your entries and results stay in this browser and are never sent anywhere. The PDF and Excel files are made on your device.
Frequently asked questions
What do I get without a pass?
Without a pass, Swab and Rinse Acceptance Limit Calculator shows the method, the limits that apply and the verdict for your input, with the first rows of a list; computed figures stay hidden until the pass. Until you unlock it, the result can’t be downloaded or printed. A Premium or Ultimate pass, a one-time payment that never renews, unlocks the full result. The pricing page lists the passes and their prices.
How do I convert a MACO into a swab limit?
Divide the MACO (in µg) by the shared product-contact surface (in cm²) to get the surface limit, multiply by the area of one swab, and divide by the extraction volume for the limit in the extract. With 50 mg over 25,000 cm² and 25 cm² swabs extracted into 10 mL: 2 µg/cm², 50 µg per swab, 5 µg/mL before recovery.
Do I divide the result by the recovery or multiply the limit by it?
Either gives the same verdict. APIC writes the correction on the result (true residue = measured ÷ recovery); the report shows the corrected residue for each result and also the limit as found, the limit times the recovery.
What recovery is acceptable?
APIC calls 90 % or more usually acceptable, requires the correction below 90 %, and says recoveries below 50 % should not be used.
How low must the LOQ be?
APIC: about half the acceptance limit or lower, and never higher than the limit. The report checks the LOQ against the limit in the swab extract and in the rinse.
What if a result is below the LOQ?
APIC reports it as the LOQ (the worst case), so a result of 3 mg/L with an LOQ of 10 mg/L counts as 10 mg/L. The report does the same and marks the row.