Identification of 5-meta-Hydroxyphenyl-5-phenylhydantoin as a metabolite of diphenylhydantoin☆

Abstract 5- meta -Hydroxyphenyl-5-phenylhydantoin has been identified in conjugated form in the urine of dogs and patients treated with diphenylhydantoin (DPH). This metabolite appears to be the major product of the hydroxylation of DPH in dogs, but it accounts for relatively little of the DPH hydroxylated by patients.