High Performance Liquid Chromatography-Tandem Mass Spectrometric determination of carcinogen nitrosamine impurities from pharmaceuticals and DNA binding confirmation aided by molecular docking application

Background and Aims: Nitrosamines are amine compounds attached to a nitroso group. The reaction of amines and nitrosating agents forms nitrosamines. Nitrosamine impurities are classified as Class 1 based on the carcinogenicity and mutagenicity data by ICH M7 (R1). The recent discovery of nitrosamines in some pharmaceutical products has caused concern. Nitrosamines are carcinogenic, so it is necessary to determine the possible nitrosamines in pharmaceutical products. Methods: An Inertsil ODS-3, (4.6x250 mm, 5 mu m) column was used for separation. A triple quadrupole mass detector with electrospray Ionisation (ESI) was used for detection. Multiple reaction monitoring (MRM) was used for quantification. The transition ions are 75.1 > 43.3 for NDMA and 103.0 > 75.1 for NDEA. The calibration curves consist of 5 concentration levels, including NDMA and NDEA (5, 10, 50, 100, 150 ng/mL). The mean r2 value was 0.997 for NDMA and 0.999 for NDEA. For NDMA and NDEA, LOD: 2 ng/mL, LOQ: 5 ng/mL. Results: Comprehensive in silico and in vitro results indicate that the method has good accuracy and precision. Conclusion: DNA binding interactions of the molecules NDMA and NDEA, were investigated through the molecular docking and molecular dynamics methods. Molecular Docking simulations showed that these small organic molecules have high-affinity scores and strongly bind to the minor groove of the hDNA via strong hydrogen bonds.