Determination of Tobramycin Eye Drops by HPLC-ELSD

OBJECTIVE To establish an HPLC - ELSD method for the content determination of tobramycin eye drops. METHODS In this method, the column was Agilent Zorbax SB - C18 (4.6 mm×250 mm, 5 mm); The mobile phase consisted of 0.2 mol·L-1 trifluoroacetatic acid solution-methanol (92∶8) at a flow rate of 0.8 mL·mL-1. The drift tube temperature was set at 45 ℃, and the pressure of nebulizing gas was 3.5 bar. RESULTS The linear range was 55.6-1396.7 μg·mL-1(r=0.999 7). The limit of detection and quantification was 0.15 μg·mL -1 and 0.45 μg·mL -1 respectively. An average recovery of 99.0% with a RSD of 1.05% (n=9) was obtained. The precision for content determination of tobramycin was good (RSD = 0.8%, n=9). CONCLUSION The method is simple, accurate and reliable. It is suitable for the routine quality control of tobramycin eye drops preparations.