RESUMO
Aim To explore the alternative study on rat blood pressure method and HPLC method for vasopressin impurity test of oxytocin injection from biological extraction. Methods The HPLC method for the vasopressin impurity test in vitro was established and validated. The bio-extrac tion oxytocin injection samples and simulated samples were examined for vasopressin impurity by HPLC and rat blood pressure methods respectively. Results Vasopressin and adjacent impurity peaks were successfully separated by the established method. In the range of 210~13 330 IU•L -1the concentration of vasopressin had a good linear relationship with its peak area with r=0.999 9. The results of HPLC method were consistent with the biological examination method-rat blood pressure method in the current standard. Conclusions The method is proved to be specific, sensitive, and accurate, which can be used as a test method for vasopressin impurity to replace the rat blood pressure method in the current standard.