Comparision of high-resolution gas chromatography and high-performance liquid chromatography for simultaneous determination of lamotrigine and carbamazepine in plasma

Rapid, simple and sensitive methods have been devised for simultaneous dete rmination of lamotrigine (LTG) and carbamazepine (CBZ) in microsamples of h uman plasma by high-performance liquid chromatography (HPLC) and high resol ution gas chromatography (HRGC); both methods have been validated and compa red. The HPLC method was more sensitive than HRGC for both drugs, LTG and C BZ. The lowest quantitation limits (LOQ) of plasma LTG concentrations were 0.1 mug.mL(-1) (HPLC) and 0.5 mug.mL(-1) (HRGC); for CBZ they were 0.1 mug. ml(-1) (HPLC) and 0.25 mug.mL(-1) (HRGC). Both methods, are sensitive enoug h to work with microsamples at subtherapeutic, therapeutic and toxic concen trations, being reliable and practical for routine therapeutic monitoring o f LTG. The HPLC method proposed is suitable also for pharmacokinetic studie s orchid patient, routine therapeutic-drug monitoring where there is a need for sensitive methods and small sample sizes.