Determination of sparstolonin B by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry: application to pharmacokinetic study of sparstolonin B in rat plasma.

Sparstolonin B (SsnB), a spontaneous isocoumarin compound isolated from the tuber of Scirpus yagara Ohwi. (Cyperaceae), possesses potent anti-inflammatory and antitumor activity. In the present study, a rapid and simple UHPLC/MS/MS method for determination of SsnB in rat plasma was developed and validated. Plasma samples were pretreated by liquid-liquid extraction with ethyl acetate containing rhein as an internal standard and separated on a C18 column at 35 °C, with a gradient mobile phase consisting of acetonitrile and water containing 0.2% (v/v) formic acid within 2.1 min. MS/MS detection was accomplished in multiple reaction monitoring mode with negative electrospray ionization. The precursor-product ion transitions were m/z 266.9 [M-H](-)  → m/z 211.0 for SsnB and m/z 283.2 [M-H](-)  → m/z 239.0 for IS. The intra- and inter-day precision (RSD) was <8.98% and the accuracy (RE) ranged from -7.40 to 4.50%. The extraction recoveries ranged from 96.28 to 97.30%. The pharmacokinetic parameters were calculated using Win Nonlin53 software. The absolute bioavailability of SsnB was estimated to be 6.98%. The proposed method was successfully applied to a pharmacokinetic study of SsnB in rats after intravenous administration with a dose of 0.5 mg/kg and oral administration at a dose of 5 mg/kg.