Abstract: A high performance liquid chromatograph-evaporative light-scattering detector(HPLC-ELSD) was developed for the content determination of tulathromycin in injection. The sample was injectable formulation containing 50 mg/mL tulathromycin. The chromatographic condition were ODS C₁₈(250 μm×4.6μm,5 μm).The mobile phase was 0.02 mol/L ammonium acetate with formic acid-acetonitrile(80:20), flow rate was 1 mL/min; column temperature was 25℃; evaporative light-scattering detector(ELSD): drift tube temperature was 60℃; nebulizer heater level was 60%; gas pressure was 172.4 kpa, PMT gain was 150. The calibration curve was linear in the range of 0.01 to 0.2 mg/mL with correlation coefficient 0.9989, the spiked recoveries at three spiked concentration levels were in the range of 96.3% to 97.8%, the RSDs were 0.6% to 0.9%. The results showed that this method was simple, quick and accurate for the content determination of tulathromycin in injection.

Key words: tulathromycin; injection; HPLC-ELSD; content determination