ABSTRACT
Objective:To develop an HPLC with gradient elution method for the determination of loteprednol etabonate and the re-lated substances in loteprednol etabonate and tobramycin compound ophthalmic suspension. Methods:HPLC with gradient elution was performed with Inertsil ph phenyl column (250 mm × 4. 6 mm, 5 μm). The mobile phase A and B was 0. 25% acetic acid solution-acetonitrile (80 ∶20) and acetonitrile, respectively. The flow rate was 2. 0 ml·min-1 and the detection wavelength was 244 nm. The column temperature was 30 ℃ and the injection volume was 20 μl. Results:The main ingredient and the related substances could be well separated. Loteprednol etabonate had a good linear relationship within the range of 0. 001-1. 02 mg·ml-1(r=0. 999 9), and the average recovery was 99. 9%(RSD=0. 9, n=9). Conclusion:The assay method is sensitive, accurate and convenient with good res-olution. It can be applied to control the quality of loteprednol etabonate and tobramycin compound ophthalmic suspension.