SIMULTANEOUS RAPID HPLC DETERMINATION OF ANTICONVULSANT DRUGS IN PLASMA AND CORRELATION WITH EMIT

  • 1 January 1980
    • journal article
    • research article
    • Vol. 10  (1) , 89-94
Abstract
A method is presented for measuring simultaneously 5 anticonvulsants (primidone, ethosuximide, phenobarbital, carbamazepine and diphenylhydantoin) in [human] serum and plasma by high-performance liquid chromatography (HPLC) using alphenal (5-allyl-5-phenyl-barbituric acid) as the internal standard. All 5 drugs are separated from each other and, in the case of primidone, from its metabolite, 2-phenyl-2-ethyl-malondiamide. Total HPLC time for the separation is 7 min. The chromatography is performed on a C-8 reverse phase column with a mobile phase consisting of acetonitrile/phosphate buffer (35/65) at 25.degree. C. The eluted drugs are detected at 220 nm and quantitated from their peak heights relative to that of the internal standard. The lower limits of detection for each drug is 200 ng/ml for primidone, 1000 ng/ml for ethosuximide, 200 ng/ml for phenobarbital, 100 ng/ml for carbamazepine and 200 ng/ml for diphenylhydantoin. Analytical recoveries for the 5 drugs were 97-107%. Correlation of results for 187 specimens by enzyme-immunoassay (EMIT) was 0.981 for primidone, 0.827 for ethosuximide, 0.975 for phenobarbital, 0.889 for carbamazepine and 0.990 for diphenylhydantoin. In the HPLC assay, ethotoin interfered with phenobarbital and phensuximide interfered with carbamazepine.