The biosynthesis of hydroxynalidixic acid.

Analytical methods have been worked out for the study of the human metabolism of nalidixic acid. Under pathological conditions the excretion of its metabolites differed from that observed in healthy volunteers. The cause of these variations was studied on the basis of individual excretion curves. The results showed that human and microbial biotransformations were identical. The possibilites offered by the new methods in drug research are discussed.