Simultaneous Determination of Ethacridine Lactate, Triamcinolone Acetonide and Miconazole Nitrate in Compound Miconazole Cream by Conversion Wavelength HPLC

The sample of compound miconazole cream (about 1 g) was added into 25 mL of ethanol and heated for disolution. After cooling, the solution was made up to 50 mL with ethanol and mixed well. After freezing for 1 h, the solution was filtrated immediately with filter paper. The filtrate was taken and cooled to room temperature. Agilent Eclipse Plus C₁₈ column (250 mm×4.6 mm, 5 μm) was used as stationary phase for seperation, with a mixture of methanol, acetonitrile and 30 g·L^-1 ammonium acetate solution as mobile phase for gradient elution. The detection wavelengths for ethacridine lactate, triamcinolone acetonide and miconazole nitrate were 270, 240, 230 nm, respectively. The linear ranges of ethacridine lactate, triamcinolone acetonide and miconazole nitrate were 40-180, 40-200, 800-401 mg·L^-1, and the detection limits (3S/N) were 0.75, 1.06, 2.18 mg·L^-1, respectively. The method was used to determine ethacridine lactate, triamcinolone acetonide and miconazole nitrate in compound miconazole cream, giving results in contency with the marked values. Values of recovery obtained by standard addition method were in the range of 96.1%-104%,and RSDs (n=6) were less than 1.0%.