Simultaneous determination of phenobarbitone,phenytoin and carbamazepine in human plasma by RP-HPLC

Objective To establish a method for the determination of phenobarbitone(PB),phenytoin (PHT)and carbamazepine(CBZ)in human plasma by reversed-phase HPLC at the same condition. Methods Agilent Zorbax 8 nm Extend-C_(18)(5μm,4.6 mm×150mm)was used as analytical column and a mixture of V(methanol):V[V(0.1 mol/L sodium acetate):V(0.05%β-cyclodextrin)=32:18]=68:32 as mobile phase.The UV wavelength was 230 nm and flow rate was 0.8 mL/min.Results PB,PHT and CBZ were separated well.Resolving powers were all more than 1.5.The lowest detective concentrations of PB,PHT and CBZ were as following:0.380 2,0.182 3 and 0.1444μg/mL.The linear ranges were in the range of 0.4～60,0.2～30,0.2～30μg/mL,and relative recovery rates were 97.04%,96.52% and 97.09% respectively.The relative standard deviations of within-day and between-day were all less than 5.8%. Conclusion The method is simple,sensitive,convenient and reliable.It is suitable for the determination of phenobarbitone,phenytoin and carbamazepine in human plasma at clinic as normal test.