The pharmacokinetics of diethanolamine in Sprague–Dawley rats following intravenous administration

In order to better understand the potential toxicity of diethanolamine (DEA) and preparatory to physiologically-based pharmacokinetic model development, the pharmacokinetics of DEA at high and low internal dose through 96-h post-dosing were determined in female Sprague–Dawley rats administered 10 or 100 mg/kg uniformly labeled 14C-DEA via intravenous injection. Clearance of DEA from blood was calculated to be approximately 84 ml/h/kg at the low dose, increasing to approximately 242 ml/h/kg at the high dose. The primary route of excretion of administered radioactivity, approximately 25–36%, was via the urine as parent compound. A majority of the administered radioactivity was recovered in the tissues of treated rats, especially in the liver and kidneys, suggesting a propensity of DEA or its metabolites for bioaccumulation. An accumulation of radioactivity also occurred gradually in the red blood cells from about 6–96 h post-dosing. Some evidence of dose dependency in the fate of iv-administered DEA was observed, suggesting that saturation of the bioaccumulation process(es) occurred at a dose level of 100 mg/kg.