RESUMO
Aim To develop a sensitive, specific and accurate method for the pharmacokinetic study of QO-58 ( a novel M channel opener ) in rats after intragas-tric ( ig) and intravenous ( iv) administration. Meth-ods QO-58 was administered at the doses of 25,50, 100 mg · kg-1 ( ig ) and at single dose of 100 mg · kg-1(iv), respectively. Blood samples were obtained at intervals after each administration. Plasma samples were deproteinized with acetonitrile after addition of in-ternal standard, and detected by RP-HPLC. The main parameters of pharmacokinetics were calculated by DAS2. 1. 1 software. Results The calibration curve in plasma was linear over the range of 0. 1 ~160 mg · L-1 in rat plasma, and the limit of detection ( LOD) was 0. 1 mg · L-1 . The intra-day and inter-day RSD was less than 20%. The recovery of QO-58 in rat plas-ma was 89. 56% ~101. 38%. The concentration-time curves of QO-58 in rat palsma were consistent with the two-compartment model after both oral and intravenous administration. The main pharmacokinetic parameters for QO-58 following oral administration with three doses (25, 50, 100 mg· kg-1 ) in rat were as follows:Cmax (mg·L-1):8.25,16.29,18.27;T12β(h): 8.24, 5. 01, 5. 92; AUC0-∞ ( g · min · L-1 ):261. 94, 189. 57,90. 65. Conclusion The developed method is simple and specific, and is suitable for preclinical pharmacokinetic studies of QO-58 .