I am doing cleaning validation on a tablet press after compressing Acetaminophen.
I did 3 cleaning studies.
We took swab samples from 20 different locations 5cmx5cm ea location
all results cam back less than 10 ppm

after study 3, I cleaned the equipment and compressed a placebo tablet( all exipients) same weight as acetaminophen tablet 325mg and assayed the placcebo tablet for Acetaminophen. came out 0.280mg per tablet.

Can you do the MACO calculations after study 3?

How it should be done in this case given that the placebo tablet is the same as Acetaminohen taablet in weight?


Abdul Azzam

first of all
I wold like to know that what is your calculation for 10 ppm?
what about recovery study of swab?

R U included that factor?

Please clarify

moreover you can calculate MACO and justify your existing validation by interim validation review as a documented evidence.


I did 2 recovery studies one on 100 ppm Acetaminophen solution and the recovery was 80% and another one on 5 ppm and the recovery was 70 %

In the three studies I swabbed

20 areas in first study and residue of Acetaminophen was less than 10 ppm in all reas

8 areas and second study and residue of Acet was less than 10ppm

same thing for the 3rd study

now, if the placebo tablet showed it has 0.280 mg per tablet 362 mg, is this acceptable?

The calculations for 10 ppm are done by contracted lab and I did not take into cosnssideration the recovery study but the highest result of residue is 6.22 ppm.