Automated High-Pressure Liquid Chromatographic Assay for Antiepileptic Drugs and Their Major Metabolites by Direct Injection of Serum Samples

Publisher Website
Google Scholar
Abstract
A fully automated high-pressure liquid chromatographic (HPLC) assay for simultaneous quantitation of 5 antiepileptic drugs [ethosuximide (ES), primidone, phenobarbital, phenytoin and carbamazepine] and their major metabolites [phenylethylmalondiamide (PEMA), carbamazepine-10,11-dihydro-10,11-diol (CBZD), and carbamazepine-10,11-epoxide (CBZE)] in serum samples without sample pretreatment. Two other metabolites, p-hydroxyphenobarbital (HPB) and 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH), can be separated as well. Interference with serum constituents prevents a quantitative determination. Serum samples are injected onto a precolumn, the biological matrix is eluted with water, and the compounds of interest are subsequently separated on an analytical column. The anticonvulsants are eluted at 60.degree. C with a mobile phase containing acteonitrile:water (21:80 by vol) at a flow rate of 1.0-2.0 ml/min (flow-step gradient). The eluted compounds are monitored at 200 nm. Each analysis requires about 30 min. Analytical recoveries varied from 90-98%. Within-day coefficients of variation (CV) ranged from 0.9-4.9%, between-day CV from 2.8-7.6%. The lower limit of detection for all drugs is 0.2 .mu.g/ml serum, with a sample size of 100 .mu.l. At therapeutic concentrations baseline separation was achieved for all 8 compounds, and there was no interference from other drugs.

This publication has 9 references indexed in Scilit: