||Health Effects Research Lab., Research Triangle Park, NC. ;Northrop Services, Inc., Research Triangle Park, NC. ;National Inst. of Environmental Health Sciences, Research Triangle Park, NC.
Dermal absorption, distribution, and metabolism of 1,3-diphenylguanidine (DPG), widely used as an accelerator in processing rubbers and in food packaging, was studied in adult female Sprague-Dawley rats. DPG shows 10% penetration through clipped back skin of the rats in 5 days. The first-order dermal absorption rate constant as determined by least square method was 0.021 + or - 0.002 days-1 (T 1/2 = 33.6 days). Approximately 13% of the absorbed dose remained in the body in 5 days. Retention in skin, muscle, liver, intestine and fat contributed most to the body burden of DPG-derived radioactivity in 5 days. All tissues showed tissue to blood ratios greater than 1, with liver and intestine ratios of 26 at 5 days. Approximately 61% of the absorbed dose was eliminated into urine and 27% into feces in 5 days, showing rapid clearance of absorbed DPG from the body. HPLC analysis of urine revealed two major peaks (parent compound and metabolite(s)). Within 72 hr, approximately 50% of the DPG-derived radioactivity excreted in the urine was parent compound.