Determination of scutellarin in rat plasma by high-performance liquid chromatography with ultraviolet detection

A validated high-performance liquid chromatography method is described for the determination of scutellarin in rat plasma using a liquid–liquid extraction and ultraviolet (UV) absorbance detection. The separation used a Diamonsil ODS column (250 mm×4.6 mm i.d., 5 μm particle size) with an isocratic mobile phase consisting of methanol–acetonitrile–50 mM dihydrogen ammonium phosphate buffer (22:15:63 (v/v/v), adjusted to pH 2.5 with 1 M phosphoric acid). The ultraviolet detector operated at 335 nm. Plasma samples were extracted with ethyl acetate after acidification. The extraction recovery of scutellarin ranged from 68.1 to 80.5%. High selectivity and a low quantitation limit (0.050 μg/ml) were achieved. The linear range was 0.050–12.5 μg/ml, correlation coefficient r=0.9981. The method has a good reproducibility, R.S.D. values were below 7.9% for within-day and between-day precision. The method is simple, rapid, and applicable to preliminary pharmacokinetic studies of scutellarin in rats.