Simple GLC analysis of anticonvulsant drugs in commercial dosage forms.

A simple, specific GLC procedure is described for the analysis of one sedative and six anticonvulsant drugs in pharmaceutical dosage forms. Sample aliquots of ethotoin, glutethimide, mephenytoin, methsuximide, and phensuximide were shaken with or extracted into ethyl acetate, diluted with the internal standard (diphenyl phthalate) solution, injected into a gas chromatograph, and eluted from a methylsilicon column. Primidone and phenytoin samples (extracted as the free acid) required derivatization with N,O-bis(trimethylsilyl)acetamide prior to chromatography. The same temperature programming conditions and flow rate settings were used for all seven drugs. The GLC results agreed well with those obtained using the pharmacopeial methods.