Pharma Cleaning Validation – Swab Limit Calculations

Question:
How do you calculate the swab limit, once it has been extracted in solution?

Answer:
In general the calculations go as follows:

swab limit (ug residue/swab) = acceptance criteria (ug residue/cm2) X swab area (cm2) X swab recovery (%)

acceptance criteria = ug residue/cm2 of a given residue
swab area = cm2 of area swabbed
swab recovery = the percent actually detected compared to a spiked surface area of known amount of residue (amount detected/amount swabbed X 100)

To convert swab limits to test result limits by converting ug residue/swab to ug residue/mL based on the extraction volume that is used to extract the swab for analysis.

The general equation is:

test result limit (ug residue/mL) = swab limit (ug residue/swab) / mL of extraction solution.

If you need help calculating swab limits for pharmaceutical cleaning validation, contact the experts at cleaning@alconox.com.