Determining the pharmacokinetics of psilocin in rat plasma using ultra-performance liquid chromatography coupled with a photodiode array detector after orally administering an extract of Gymnopilus spectabilis

This study established ultra-performance liquid chromatography coupled with a photodiode array detector for determining psilocin and its pharmacokinetics in rat plasma after orally administering an extract of Gymnopilus spectabilis. The extract was separated on an ODS C18 column (2.3 μm, 100 mm × 2.1 mm I.D.) by gradient elution with (A) water containing 50 mM AcONH4 and (B) acetonitrile. The wavelength was set at 265 nm and the injection volume was 10 μL. Under these conditions, the calibration curve was linear over the concentration range 0.2–20 μg/mL with a correlation coefficient of r2 = 0.9992. The inter- and intraday precision levels were less than 7% and the accuracies (%) were within the range 92.0–102.5%. The method was sufficiently valid to be applied to a pharmacokinetics study of psilocin in rat plasma. The pharmacokinetic parameters of psilocin in rat plasma after the oral administration of a G. spectabilis extract were as follows: Cmax, 0.43 ± 0.12 μg/mL; Tmax, 90 ± 2.1 min; AUC0→t, 1238.3 ± 96.4 (μg/mL) min; and T1/2, 117.3 ± 40.3 min.