Simultaneous determination of phenobarbital, phenytoin and carbamazepine in human plasma by HPLC

OBJECTIVE To establish a HPLC method for the determination of phenobarbital, phenytoin and carbamazepine in human plasma. METHODS The plasma samples were extracted by dichloromethane. The separation was performed on a Shim-pack CLC-CN column. The mobile phase was composed of n-hexane-absolute ethanol-methanol (94.5:5:0.5). The detection wavelength was at 220 nm. Diaze-pam was used as the internal standard. RESULTS The linearity was obtained over the range of 0.5 - 80.0 μg·mL-1(r≥0.9994) for phenobarbital, phenytoin and carbamazepine with the average recoveries 100.69% , 99.66% and 101.01 % respectively. Intra-day RSD and inter-day RSD were less than 5.9%. CONCLUSION The method appeared to be sensitive, specific, accurate and convenient.It is suitable for the determination of phenobarbital, phenyloin and carbamazepine concentrations in human plasma.