OBJECTIVE To evaluate the mutagenicity of potential process impurities with warning structure in the synthetic process of avanafil, so as to provide guidance and basis for the classification and control of related substances of avanafil.

METHODS The potentially genotoxic impurity E(Imp-E) of Avanafil with warning hydrazide-structure was synthesized by chemical method and evaluation and classification were made according to The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use(ICH) M7 guidelines. Two complementary quantitative structure-activity relationship(QSAR) evaluation systems(Derek and Sarah) based on expert rules and statistical principles were respectively employed to conduct preliminary predictions of the genotoxicity of Imp-E, and the Ames test was carried out to further verify Imp-E.

RESULTS Derek prediction results for Imp-E were all positive, and were classified into Class 3 according to the ICH M7 guidelines. In Ames test, the number of revertant colonies of Imp-E in the presence or absence of metabolic activation system S9 in the range of 62.5−1000 μg per plate of test substance was less than 2 times of that in the solvent control group, and the test result was negative.

CONCLUSION The bacterial mutation test results of Imp-E are all negative, which can overturn the positive result based on the Derek's prediction, and these impurities can be controlled as Class 5 in ICH M7, which namely non mutagenic impurity.