p,p'-Dichlorodiphenyl sulfone metabolism and disposition in rats

p, p'-Dichlorodiphenyl sulfone (DDS) is a lipophilic monomer used extensively in the synthesis of high temperature plastics. Studies of the fate of uniformly labeled [14C]DDS in the rat have established that it is readily absorbed from the gastrointestinal tract, distributed to all tissues examined, and concentrated in adipose tissue. After intravenous administration of 10 mg/kg and determination of the time course of DDS distribution, increasing accumulation of DDS in adipose was observed up to 24 hr, followed by slow elimination with a half-life of approximately 12 days. DDS equivalents in tissues were primarily (> 90%) parent compound, whereas excreted DDS equivalents were primarily (> 80%) present as metabolites. On repeat oral dosing at 10 mg/kg, levels of DDS in tissues seemed to reach steady state after approximately 2 weeks, at which time the concentrations in adipose reached 265 micrograms/g tissue. Hepatic cytochrome P450 (CYP) content, ethoxyresorufin O-deethylase activities, and levels of metabolites arising from phase I metabolism were doubled after repeat oral administration of DDS, but benzphetamine N-demethylase activity was unchanged. Thus, it seems that DDS induces CYP1A forms, but not CYP2B isozymes. DDS-derived radioactivity was excreted primarily in feces and to a lesser extent in urine as a phenolic metabolite and its glucuronide. The aglycone of this glucuronide was isolated and characterized by NMR and MS as 3-hydroxy-4,4'-dichlorodiphenyl sulfone.