Sensitive determination of kaempferol in rat plasma by high-performance liquid chromatography with chemiluminescence detection and application to a pharmacokinetic study

A simple and sensitive method based on high-performance liquid chromatography (HPLC) coupled with chemiluminescence detection was developed for the quantitation of kaempferol (KA) in rat plasma. Isorhamnetin (IS) was used as an internal standard. Plasma samples were prepared only by acidification with 20% phosphoric acid and protein precipitation using methanol. Good separations of kaempferol and internal standard were achieved with an isocratic elution using a mobile phase consisting of methanol and aqueous 0.4% phosphoric acid (47:53, v/v) within 25 min. The detection limit for kaempferol was 1.0 × 10−9 g/ml. The mean accuracy was within 80.0–100.2%, and the intra- and inter-day precision had RSD (%) < 5.0. The sample preparation method was able to produce high recovery (≥80.0%). The proposed method with wide linear range has been successfully applied to a pharmacokinetic study in SD rats after oral administration at a dose of 2500 or 1250 mg/kg bodyweight (BW) kaempferol. Kaempferol concentration was detectable in plasma up to 24 h post-dosing, and the pharmacokinetic parameters of Tmax, Cmax, AUC0−∞, MRT0−∞, and T1/2 of kaempferol were reported.