Objective To establish a ultrahigh-performance liquid chromatography-orbitrap high-resolution mass spectrometry(UHPLC-Orbitrap HRMS)method for the determination of the genotoxic impurity N-nitroso propranolol(NPPN)in propranolol hydrochloride sustained-release tablets.Methods The test sample was ultrasonically extracted using methanol as the solvent,then centrifuged and filtered before injection analysis.Chromatographic separation was performed using a 2.7 μm particle size C18 UHPLC column with a mobile phase of 0.1％formic acid(A)in water and 0.1％formic acid(B)in acetonitrile,using gradient elution.Mass spectrometry was conducted with an HESI ion source in positive ion parallel reaction monitoring(PRM)scan mode,monitoring the NPPN fragment ion at m/z 72.080 8,and quantification was performed using the standard curve method.Results The calibration curve was in good linearity in the range of 0.51-20.30 ng·mL-1 with excellent correlation coefficient(r)of 0.9999.The recoveries of NPPN at three levels(low,medium,and high)were in the range of 95.4％～98.3％,while the RSDs were from 2.5％to 4.2％.The limit of detection(LOD)was 0.20 ng·mL-1 while the limit of quantitfication(LOQ)was 0.51 ng·mL-1.This analytical method was used to determine NPPN in six batches of propranolol hydrochloride sustained release tablet samples.NPPN was detected in all six samples,among which the detection amount of 3 batches have exceeded the acceptable limit.Conclusion This method is sensitive,accurate,and fast,making it useful for pharmaceutical companies in controlling production processes and providing robust technical support for regulatory authorities.

Objective To establish a ultrahigh-performance liquid chromatography-orbitrap high-resolution mass spectrometry(UHPLC-Orbitrap HRMS)method for the determination of the genotoxic impurity N-nitroso propranolol(NPPN)in propranolol hydrochloride sustained-release tablets.Methods The test sample was ultrasonically extracted using methanol as the solvent,then centrifuged and filtered before injection analysis.Chromatographic separation was performed using a 2.7 μm particle size C18 UHPLC column with a mobile phase of 0.1％formic acid(A)in water and 0.1％formic acid(B)in acetonitrile,using gradient elution.Mass spectrometry was conducted with an HESI ion source in positive ion parallel reaction monitoring(PRM)scan mode,monitoring the NPPN fragment ion at m/z 72.080 8,and quantification was performed using the standard curve method.Results The calibration curve was in good linearity in the range of 0.51-20.30 ng·mL-1 with excellent correlation coefficient(r)of 0.9999.The recoveries of NPPN at three levels(low,medium,and high)were in the range of 95.4％～98.3％,while the RSDs were from 2.5％to 4.2％.The limit of detection(LOD)was 0.20 ng·mL-1 while the limit of quantitfication(LOQ)was 0.51 ng·mL-1.This analytical method was used to determine NPPN in six batches of propranolol hydrochloride sustained release tablet samples.NPPN was detected in all six samples,among which the detection amount of 3 batches have exceeded the acceptable limit.Conclusion This method is sensitive,accurate,and fast,making it useful for pharmaceutical companies in controlling production processes and providing robust technical support for regulatory authorities.