Determination of Concentration of Nifekalant in Human Plasma by HPLC Method and Investigation of Its Pharmacokinetics

Abstract

Objective: To establish a HPLC method for determining the concentrations of Nifekalant in human plasma and to evaluate its pharmacokinetic characteristics. Method: A ODS3 (250 mm × 4.6 mm 5 µm) column was used to separate Nifekalant in plasma with a mobile phase of a mixture of ammonium acetate (0.1 mol/L)-methanol- methyl cyanide (440:180:180, V/V) at a flow rate of 1ml/min. Nifekalant was detected at 270nm. The Nifekalant plasma concentrations were determined after intravenous injection and its pharmacokinetic parameters were calculated by DAS2.0. Results: The linear range of the standard curve of Nifekalant was 5~1000ng/mL, and the determination limit was 5 ng/mL. The extraction recoveries were more than 80%, intra-day and inter-day RSD were less than 6.23%. The main pharmacokinetics of Nifekalant after intravenous injections 0.3 mg/kg or 0.4 mg/kg Nifekalant Hydrochloride Injection were as follows, t_1/2 (1.545±0.382) h and (1.344±0.188) h, T_max 0.08 h and 0.08 h, C_max (230.946±54.023) ng/mL and (358.615±73.948) ng/mL, AUC_0-5 (193.526±45.194) ng/mL/h and (285.608±46.569) ng/mL/h, AUC_0-8 (209.895±48.117) ng/mL/h and (302.439±50.191) ng/mL/h, MRT (1.179±0.147) h and (1.128±0.085) h, CL(1.499±0.353) L/kg/h and (1.354±0.22) L/kg/h, V (3.402±1.443) L/kgand (2.596±0.353) L/kg, and after intravenous infusion of 0.4mg/kg/h Nifekalant Hydrochloride Injection were_{C ss} as follows, t_1/2 (1.348±0.227) h, C^ss_max (444.303±88.122) ng/mL, AUC_0~12 (2609.020±498.200) ng/mL/h, AUC_0-8(2627.332±499.887) ng/ml/h, MRT (3.726±0.182) h, T_max (1.603±2.259) h, CL (0.315±0.062 ) ng/mL/h, V(0.609±0.149) L/kg, respectively. Conclusions: The method is sensitive, fast and accurate. It is suitable for therapeutic Nifekalant monitoring and its pharmacokinetic studies.