Identification of cyclic metabolites of isopropylated phenyl phosphates in rabbit bile.

Some organophosphorous compounds, especially tri-o-cresylphosphate (TOCP), induce delay neuropathy. The cyclic saligenin phosphate (PSP) has been suggested to be the active metabolite of the protoxicant TOCP. The o-isopropylated triphenyl phosphates have been proven not to be neurotoxic. Studying the metabolism of these compounds we found the following cyclic metabolites: 2-phenyl-4H-4,4-dimethyl-1,1,3,2-benzodioxaphosphoran-2-oxide and 2-(o-isopropylphenyl)-4H-4,4-dimethyl-1,1,3,2-benzodioxaphospho ran-2-oxide. Additionally, monohydroxylated metabolites of the parent esters were detectable. The effect of glucuronidation on the formation of the cyclic metabolites is discussed in this paper.