Determination of ulipristal acetate and its related substances by HPLC

Objective: To establish high performance liquid chromatography(HPLC)methods for the determination of ulipristal acetate and its related substances. Methods: Wondasil C₁₈ column(250 mm×4.6 mm, 5 μm) was used for the determination of ulipristal acetate. The mobile phase was acetonitrile-water(70:30)with the flow rate set at 1.0 mL·min^-1. The detection wavelength was 302 nm and column temperature was 25°C. Apollo C₁₈ column(250 mm×4.6 mm, 5 μm)was used for detecting the related substances, with the mobile phase consisting of 10 mmol·L^-1 potassium dihydric phosphate buffer(containing 0.05% triethylamine)-acetonitrile(40:60). The flow rate was 1.0 mL·min^-1. The detection wavelength was 260 nm and column temperature was 25°C. Results: The calibration curve of ulipristal acetate was linear in the range of 22.90 to 68.70 μg·mL^-1(A=52353C-59224, r=0.9989). Repeatability was good(RSD=0.24%). Ulipristal acetate and its related substances were completely separated. Conclusion: The methods are simple, specific, and accurate with good reproducibility, which can be used for the determination of ulipristal acetate and its related substances.