[Determination of quinidine in plasma and its pharmacokinetics by high pressure liquid chromatography].

Reverse-phase liquid chromatographic assay method was used for quantitative analysis of quinidine in plasma. The mobile phase was a mixture of methanol: water: glacial acetic acid (1000: 10: 0.5 v/v) and the flow rate was 1.5 mL/min. Dyclonine was used as an internal standard. The retension times for quindine and dyclonine were 4.8 and 8 min, respectively. Plasma levels could be assayed for concentrations of 0.5-10 microg/ml. Pharmacokinetic parameters were measured in 5 healthy volunteers and 5 male rabbits after oral administration of quinidine 200 mg/kg, respectively. The mean+/-SD were as follows; Men: k=0.24+/-0.22 h-1, Ka=1.3+/-0.8 h-1, t1/2=7+/-6 h, Cmax=0.5+/-0.3 microg/ml, tmax=2+/-0.58 h, AUC0-24 h=7.3+/-6.4 microg.h/ml. Rabbits: Ke=0.2+/-0.07 h-1, t1/2=4.14+/-1.95 h, Cmax=5.9+/-1.8 microg/ml, tmax=1.91+/-0.32 h, AUC0-24 h=60.2+/-12.6 microg.h/ml. The HPLC method described is rapid, accurate for the clinical monitoring of quindidine concentration in plasma.