[Simultaneous estimation of phenobarbitone and valproic acid in the plasma by high performance liquid chromatography...

The authors describe a method of simultaneous estimation of phenobarbitone and valproic acid in the blood. After extraction with ether, these substances were estimated by high performance liquid chromatography. They were separated on a mu Bondapack C18 column. The detection involved a colorimetric procedure based on variation in colour of a solution of bromocresol purple. The technic used is simple, its reproducibility is satisfactory (coefficients of variation of 7.6% for phenobarbitone and 2.3% for valproic acid). The sensitivity was 13.8 mumol/l for phenobarbitone and 11.1 mumol/l for valproic acid. Parallel estimations by gas chromatography led to comparable results. This method is of interest in the supervision of anticonvulsant treatments, especially in pediatrics.