Update of the CMDh's Q&A Document on Nitrosamine Impurities

CMDh added an option to to introduce a limit in the specification of the FP as a possibility for lifting the condition on the risk assessment (RA) for the finished product. It would be nice if we could get some guidance from CMDh on how to actually set limits, particularly for complex nitrosamines. Until now we don’t have clear guidance on how to perform acceptable QSAR/read-across analysis to set acceptable intakes (AIs); a negative Ames test is not currently accepted (even when using the modified protocols); the Comet assay is not accepted yet; the molecular weight adjustment (molar ratio) method is not yet accepted; the criteria for selection of adequate surrogates from the LCDB to read-across from to complex nitrosamines is not clear; which TD50 should be used from the LCDB, the harmonic mean TD50, the lowest Gold TD50, the lowest Lhasa TD50? The HAs themselves have done some read-across for the nitrosamines currently listed in their guidelines, but their selection of surrogates is questionable as there are better surrogates to be found. Too many issues are still unclear and the burden falls on the industry to try and guess which method will be accepted by the agencies. Setting an acceptable limit is almost like playing a game of roulette.