Development of a size-exclusion HPLC method with evaporative light-scattering detection for the quantitation of...

A rapid and accurate size-exclusion HPLC method for the quantitation of polysorbate 80 (PS80) in Houttuynia cordata injection, a Chinese traditional medicine, was developed and validated. The assay was conducted on an Agilent 1100 HPLC system with a TosoHaas TSKgel G2000 SWxL column (30 cm x 7.8 mm, 5 pm particle size) and an Alltech evaporative light-scattering detector (ELSD) 2000. The mobile phase was 20 mmoL/L ammonium acetate-acetonitrile (90 + 10, v/v) delivered at a flow rate of 0.6 mL/min under isocratic conditions. The ELSD was operated in the impactor "off" mode, the drift tube temperature was set at 110 degrees C, and nitrogen flow was maintained at 2.3 L/min. The LOD was 0.25 mg/mL. Linearity was obtained between the log of concentration (C) and the log of peak area (Y) of PS80 in the range of 0.5-20 mg/mL according to the equation: Log Y 1.4529 Log C - 0.8232 (r2 = 0.9976). An RSD of 1.6% (n = 6) for the determination demonstrated the good precision of the optimized method. PS80 content in several commercial H. cordata injection products from different manufacturers was determined. The data for PS80 content is useful in evaluation of the safety of the products from different manufacturers.