Establishment and validation of the determination method for the related substances in carbetocin injection

An HPLC analytical method was developed to determine the related substances in carbetocin injection. The method was performed on a Waters Xbridge C₁₈ column (150 mm×3 mm, 3.5 μm) with 0.30 mg/mL ammonium acetate-19% acetonitrile aqueous solution as mobile phase A and mobile phase A-acetonitrile (1∶1) as mobile phase B. The detection wavelength was 220 nm. Gradient elution was performed at the flow rate of 0.8 mL/min and the column temperature of 60℃. The method was validated for system applicability, specificity, linearity and range, accuracy, with the results that the 9 impurities of carbetocin injection showed good linearity (R²>0.999) with peak area in their respective concentration range, and that the method had good precision (RSD<5%). This method is suitable for the simultaneous determination of carbetocin and its 9 impurities in carbetocin injection and can provide a theoretical basis for the quality control of the carbetocin injection.