Solid-phase extraction and high-performance liquid chromatographic analysis of prednisone adulterated in a foreign herbal medicine

Prednisone was detected in a herbal medicine from Southeast Asia using thin layer chromatography (TLC) and ultraviolet spectroscopy (UV). After treating with solid-phase extraction (SPE), the sample was further assayed by high-performance liquid chromatography (HPLC). The sample solution was achieved with a silica gel cartridge conditioned with methanol and chloroform in sequence, and then eluted with dichloromethane-isopropanol (6:4, v/v). Separation was conducted with an Inertsil ODS-80A reversed-phase column using isocratic elution with acetonitrile and water (3:7, v/v) as mobile phase. Fludrocortisone acetate was used as in internal standard and detection wavelength was at 240 nm. Calibration curve of standard prednisone was constructed in (lie range of 10.0-200.0 mug/mL. The content of adulterated prednisone was 5.5 mg/21g sample.