Single extraction GLC analysis of six commonly prescribed antiepileptic drugs

A simple gas-liquid chromatographic technique for the quantitation of ethosuximide (Zarontin), methsuximide (Celontin), mephobarbituate (Mebaral), phenobarbituate, primidone (Mysoline), and diphenylhydantoin (Dilantin) is described. The drugs and internal standards are extracted from whole uncoagulated blood using an organic solvent, re-extracted to eliminate interferences, and chromatographed using temperature programming on 3% OV-225. The results compare very favorably and eliminate some difficulties associated with derivation methods.