Objective:A new degradation impurity oxazolidinone,which was not detected by the original relevant sub-stance method,was discovered and confirmed in azacitidine for injection.A high-performance liquid chromatography-mass spectrometry(HPLC-MS)method was established to determine its content.Methods:The Welch Ultimate HILIC Amide(4.6 mm × 150 mm,5 um)chromatographic column was used,with 10 mmol·L-1 ammonium formate water ace-tonitrile(20∶80)as the mobile phase,column temperature of 30 ℃,injection volume of 2 μL,flow rate of 0.8 mL·min-1.The ion source was ESI+,with a single quadrupole mass analyzer monitoring the ion mass-to-charge ratio of 176.Results:The linear relationship of oxazolidinone was good within the range of 0.473-23.649 μg·mL-1,with an aver-age recovery rate(n=9)of 101.4％and RSD of 7.30％;The quantification limit is 0.473 μg·mL-1(concentration percentage 0.09％),and the detection limit is 0.236 μg·mL-1(concentration percentage 0.05％).Conclusions:The method is highly applicable for evaluating the content of oxazolidinone in the product during storage.The results indica-ted that the method could accurately reflect its increasing trend,compensating for the previous lack of impurity control and providing a reference for the product's quality control.

Objective:A new degradation impurity oxazolidinone,which was not detected by the original relevant sub-stance method,was discovered and confirmed in azacitidine for injection.A high-performance liquid chromatography-mass spectrometry(HPLC-MS)method was established to determine its content.Methods:The Welch Ultimate HILIC Amide(4.6 mm × 150 mm,5 um)chromatographic column was used,with 10 mmol·L-1 ammonium formate water ace-tonitrile(20∶80)as the mobile phase,column temperature of 30 ℃,injection volume of 2 μL,flow rate of 0.8 mL·min-1.The ion source was ESI+,with a single quadrupole mass analyzer monitoring the ion mass-to-charge ratio of 176.Results:The linear relationship of oxazolidinone was good within the range of 0.473-23.649 μg·mL-1,with an aver-age recovery rate(n=9)of 101.4％and RSD of 7.30％;The quantification limit is 0.473 μg·mL-1(concentration percentage 0.09％),and the detection limit is 0.236 μg·mL-1(concentration percentage 0.05％).Conclusions:The method is highly applicable for evaluating the content of oxazolidinone in the product during storage.The results indica-ted that the method could accurately reflect its increasing trend,compensating for the previous lack of impurity control and providing a reference for the product's quality control.