[Simultaneous high performance liquid chromatographic determination of 8 anti-epileptics and sedatives in plasma. Use of a radial compression column system].

The authors describe a method of assaying anti-epileptic and sedative drugs by high performance liquid chromatography. This method allows for simultaneous separation and quantification of these drugs (Ethosuximide, Primidone, Phenobarbital, Beclamide, Prominal, Diphenylhydantoin, Glutethimide, Carbamazepine) in a relatively short analysis time, by means of a system of radial compression of the column. The serum is acidified and extracted by ethyl acetate. After evaporation, the residue is taken up in the mobile phase. The various drugs are eluted in a 10 micron Rad-Pak C 18 column with a mobile phase consisting of a mixture of methanol and water with a flow rate of 4 ml/min. The chromatograph is read at 200 nm and the separation is effective in about 16 minutes. The yield is between 75 and 100 per cent and the repeatability of the method is good (C. V. less than 9 per cent). The originality of the method resides in the assay of drugs such as beclamide, methylphenobarbital and glutethimide at the same time as the major anti-epileptics.