Simultaneous determination of carbamazepine and its epoxide and transdiol metabolites in plasma by microbore liquid chromatography.

Simultaneous monitoring of carbamazepine and its metabolities is helpful in providing information on the induction process via the epoxide-diol route. The present method involves the liquid-chromatographic analysis of 1.0 mL of plasma for carbamazepine at concentrations of 0.025 to 4.0 mg/L and for both the 10,11-epoxide and 10,11-transdiol metabolites at concentrations of 0.01 to 1.0 mg/L. Weighted regression equations, expressing peak area ratios as a function of concentrations of carbamazepine and its epoxide and transdiol metabolites in the standards, were used to determine concentrations in plasma samples.