TOTALLY AUTOMATED-ANALYSIS BY ROBOTIZED PREPSTATION AND LIQUID-CHROMATOGRAPHY - DIRECT-SAMPLE ANALYSIS OF FELBAMATE

A totally automated analysis of felbamate was developed by using a rob otized PrepStation for extraction, followed by automated liquid chroma tographic (LC) analysis and data reduction. This is one of the newer d irect-sample analysis approaches by LC. Felbamate was a previously app roved antiepileptic agent used to treat partial seizures with and with out generalization and to treat Lennox-Gastaut syndrome in pediatric p atients. However, due to the reported incidences of aplastic anemia, i ts clinical application was recently restricted to the treatment of th e latter syndrome. The automated assay using Bench Supervisor, PrepSta tion, and LC, based on a previously developed manual method, used 200 mu l of serum standards, quality control, or patients' plasma. These w ere mixed with 600 mu l of internal standard (IS) W509 dissolved in ac etonitrile for protein precipitation. After axial centrifugation and s tanding, aliquots of the clear supernatant were transferred and washed with hexane. Aliquots of the supernatant were transferred and injecte d into a high-performance liquid chromatograph (HPLC). HPLC parameters included an mu Bondapak C-18 column, phosphate/acetonitrile (8:2) as mobile phase, and detection at 214 nm. Retention times were 2.9 and 4. 2 min for felbamate and IS, respectively. Calibration was linear for c oncentrations from 10 to 200 mg/L with r > 0.994. Precision studies sh owed coefficients of variation ranging from 2.7% to 8.8%. Correlation with the manual method showed that r = 0.934, slope = 1.048, intercept = -2.642, and n = 21. Phenobarbital coeluted with the IS. This study demonstrated the feasibility of using a robotized, automated method fo r monitoring felbamate, readily extended to monitoring other antiepile ptic drugs with minimal modification.