Carbamazepine, carbamazepine-10,11-epoxide and phenytoin concentrations in brain tissue of epileptic children

Abstract

Carbamazepine (CBZ), carbamazepine-10,11-epoxide (CBZ-epoxide) and phenytoin (DPH) were measured in brain tissue in 2 epileptic children undergoing temporal lobectomy. The patients were treated with these anticonvulsants for 2 yr. The CBZ concentration in brain tissue was higher or equal to the plasma concentration. Brain/plasma ratio for CBZ was 1.0 and 1.4, respectively. Brain/plasma ratio of CBZ-epoxide was 1.0. Concomitant treatment with DPH increased the percentage of CBZ-epoxide relative to CBZ in both brain and plasma. In white brain substance the concentration of CBZ, CBZ-epoxide and DPH was higher or equal to the corresponding concentration in grey substance. No major age-related differences in the distribution of antiepileptic drugs between brain and plasma in these 2 children compared to adult epileptic patients were noted. A new quantitative TLC method for the determination of DPH and phenobarbital in brain tissue and plasma was described.