Quantification of 3-n-butylphthalide in beagle plasma samples by supercritical fluid chromatography with triple quadruple mass spectrometry and its application to an oral bioavailability study.

A high-throughput, rapid, sensitive, environmentally friendly, and economical supercritical fluid chromatography with triple quadruple mass spectrometry method was established and validated for the first time to determine a cerebral stroke treatment drug named 3-n-butylphthalide in dog plasma. Plasma samples were prepared by protein precipitation with methanol and the analytes were eluted on an ACQUITY UPC(2TM) HSS-C(18) SB column (3 × 100 mm, 1.8 μm) maintained at 50°C. The mobile phase comprised supercritical carbon dioxide/methanol (90:10, v/v) at a flow rate of 1.5 mL/min, the compensation solvent was methanol at a flow rate of 0.2 mL/min and the total run time was 1.5 min per sample. The detection was carried out on a tandem mass spectrometer with an electrospray ionization source. Calibration curves were linear over the concentration range of 1.02-1021.00 ng/mL (r(2) ≥ 0.993) with the lower limit of quantification of 1.02 ng/mL. The intra- and inter-day precision values were below 15% and the accuracy was from 97.90 to 103.70% at all quality control levels. The method was suitable for a pharmacokinetic study of 3-n-butylphthalide in beagle dogs.