RESUMO
Objective: To establish a determination method for the related substances in josamycin and josamycin tablets by HPLC. Methods:High performance liquid chromatography was used. The column was Ultimate-AQ-C18(250 mm ×4.6 mm,5 μm), the mobile phase respectively was mobile phase A of 0. 2 mol·L-1 tetrabutylammonium hydrogen sulphate R-0. 2 mol·L-1 disodium hydrogen phosphate(pH 3. 0)-acetonitrile R-water(3∶5∶24∶68) and mobile phase B of 0. 2 mol·L-1 disodium hydrogen phosphate (pH 3. 0)-acetonitrile R-water(5∶50∶45). The flow rate was 1. 5 ml·min-1 with the detection wavelength of 232nm. The column temperature was 50℃. Results:The main component josamycin had a good separation with the other related substances. The resolution between josamycin and the related substances with the relative retention time of 1. 1-fold of josamycin was above 1. 7. The detection limit of josamycin was 1. 43ng. In josamycin raw materiel and josamycin tablets, the percentage of related substance A and B was less than 1. 5%. The percentage of related substance D was below 2. 0%. The percentage of related substance E was less than 3. 0%. The percentage of the other maximum related substances was less than 1. 0%. The percentage of all related substances was less than 12%. The percentage of related substance C was less than 1. 0% in josamycin raw materiel while 3. 0% in josamycin tablets. Conclusion:The method is accurate, sensitive and reliable in the determination of related substances in josamycin and josamycin tablets.
RESUMO
OBJECTIVE:To establish a mercury-free perchloric acid potentiometric titration method for the content determination of rocuronium bromide.METHODS:Mettler DG113-SC was used as the composite electrode.The potentiometric titration was performed with glacial acetic acid and acetic anhydride as solvents and perchloric acid(0.1 mol?L-1) as titration.The method was compared with that stated in European Pharmacopeia.RESULTS:The linear range of rocuronium bromide was 0.150 1～0.401 3 g(r=0.999 9) with an average recovery within 99.90%～99.98%.The detection limit was 1.71 mg.There was no difference between results detected by two methods.CONCLUSION:The method is simple,sensitive and accurate for the content determination of rocuronium bromide.