Development and evaluation of method for simultaneous determination of phenobarbital and diphenylhydantoin in plasma by high-pressure liquid chromatography

A procedure for the simultaneous analysis of diphenylhydantoin and phenobarbital in plasma by high-pressure liquid chromatography was developed and evaluated. Separation is effected on a porous particle silicic acid column with chloroform dioxane-isopropanol-acetic acid (310:9.7:1.0:0.1 by volume) and is monitored at 254 nm. Results of the procedure were compared with results of a GLC assay.