The active ingredient sampling for cleaning validation is done by swabbing the equipment after it is dried. However,may be due to the volatility of nitrosamine impurities, the swab recovery rate is only a few percent (lower than 50%). The current method of swab recovery is sampling immediately after coating the surface with nitrosamine impurities, and also stipulates that the cleaning validation sampling of nitrosamine impurities is to swab the equipment immediately after cleaning. Is this approach feasible?
Data from the cleaning design can be helpful to justify the cleaning approach, e.g. solubility of the nitrosamine in the used cleaning solvents or mixture (normally not a problem due to low amounts), risk for formation during cleaning, next to the volatility vs. cleaning process considerations and (last) rinse liquid testing for the nitrosamine.