Simple high-performance liquid chromatographic method to monitor vigabatrin, and preliminary review of concentrations determined in epileptic patients

A simple and rapid high-performance liquid chromatographic method has been developed for the determination of vigabatrin concentrations in plasma or s erum. The assay uses only 100 mu L of specimen and has been found to be lin ear over a concentration range of 1 to 50 mg/L. The limit of detection has been determined as 1 mg/L, and the between-batch coefficient of variation f or the two internal quality controls routinely analysed (n = 33) has been f ound to be less than 5%. There was no evidence of interferences in the assa y from other commonly prescribed anti-epileptic drugs. This method has been applied to routine clinical specimens to determine the concentration of vi gabatrin in 47 patient specimens over a 12-month period. It was found that only 63% of the male group and 53% of the female group were within the prop osed target concentration of 5 to 35 mg/L. In addition, it was found that 2 6% of the male group and 36% of the female group were found to have concent rations below 5 mg/L, which may indicate lack of compliance and/or lack of therapeutic efficacy of treatment.