A sensitive high performance liquid chromatographic assay of a new metabolite of ampicillin in man.

A sensitive, high-performance liquid chromatographic method has been developed for the determination of piperazine-2,5-dione, a new metabolite of ampicillin, in human urine. Piperazine-2,5-dione was separated from human urine on a C18-column using phosphate buffer-methanol (pH 3.5) as eluent. Subsequently, the effluent underwent a postcolumn reaction with mercurous chloride and was then detected at 305 nm. It was found that piperazine-2,5-dione was also excreted in the urine of a volunteer dosed with ampicillin.