Genotoxic impurities (or genotoxic impurities, GTIs) are compounds that directly or indirectly damage cellular DNA, produce genetic mutations or mutagenesis in vivo, and have the potential or tendency to cause cancer. Based on the significant impact of impurities on the quality of drugs, there are corresponding regulatory requirements for impurity analysis and control regardless of any drug registration declaration, and genotoxic impurities need to be tested accordingly in order to ensure the efficacy, quality and safety of drugs.
The microsource testing laboratory shared a case of genotoxic impurity detection. Referring to the requirements of the pharmacopoeia analytical method validation guidelines, the case was used to detect and develop methods for a variety of nitrosamine impurities in tablets: N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), ethylisopropylnitrosamine (NEIPA), N-nitrosodiisopropylamine (NDIPA), and N-nitrosodibutylamine (NDBA).
The sample was processed as a test solution. In addition, an appropriate amount of NDMA, NDEA, NEIPA, NDIPA and NDBA was dissolved in methanol and diluted with a blank solution to a solution containing about 10ng of NDMA and 2.7ng of NDEA, NEIPA, NDIPA and NDBA per 1ml as a reference solution, and the appropriate chromatographic column was selected to optimize the gradient conditions and mass spectrometry parameters. 10 μl of each test solution and reference solution were accurately measured and injected into the liquid chromatography-mass spectrometry respectively.
Verify method specificity, solution stability, limits of quantification and detection, linearity, accuracy, and precision. The blank solution, the reference solution, the test solution, and the 100% limit spiked test solution were injected separately, and the chromatogram was recorded. The test results showed that there was no interference in the blank solution;
The limit of detection and 6 quantification solutions were injected separately, and chromatograms were recorded, and the detection limit of NDMA was 0.1000 ng/mg and the signal-to-noise ratio was 4.23, and the detection limit of NDEA, NEIPA, NDIPA and NDBA was 0.0270 ng/mg and the lowest signal-to-noise ratio was 11.43. The peak area or relative correction factor RSD (%) of NDEA, NEIPA, NDIPA and NDBA in 6 quantification limit solutions was no more than 4.50%;
The recoveries, average recoveries and total average recoveries of nitrosamine impurities were between 86.46%~119.14% in the test solution of each limit spiked test. The recovery rate RSD (%) of each nitrosamine impurity was not more than 8.18%, and the total recovery rate RSD (%) was not more than 5.75% in each concentration of spiked solution.
The sources of genotoxic impurities may be starting materials, reagents, intermediates, catalysts and reaction by-products in the synthesis process of APIs. Micro-source detection for genotoxic impurities with very low detection limits, equipped with a number of high-sensitivity analytical instruments, combined with domain expert engineers with rich detection experience, can apply different analysis and testing methods to different types of impurities to meet the requirements of data accuracy. If you have relevant testing needs, welcome to consult the homepage!