Excretion of Triethyllead, Diethyllead and Inorganic Lead in Rabbits after Injection of Triethyl Neopentoxy Lead

Abstract

Triethyl neopentoxy lead (TEneoPOL: (C₂H₅)₃Pb[OCH₂C(CH₃)₃] liquid) was administered to rabbits in a single dose of 10mg/kg body weight (5.4mg Pb/kg body weight), and the urinary and fecal excretions of lead were measured to determine the fate of this triethyllead derivative. About 4% of the administered amount of was excreted into the urine during the 7 days after the injection; and about 68%, into the feces. In other words, the fecal excretion of total lead was about 17 times as great as the urinary excretion. About 85% of the urinary excretion of total lead was composed of diethyllead (Et₂Pb²⁺), and about 92% of the fecal excretion consisted of inorganic lead (Pb²⁺). The major chemical species of lead excreted in the urine was Et₂Pb²⁺, while the major species excreted in the feces was Pb²⁺. These results were similar to those of administration of tetraethyllead (Et₄Pb) to rabbits. One of the 7 rabbits died on the day following the injection, and TEneoPOL, a triethyllead derivative, proved to be no less toxic than Et₄Pb. However, this compound is immediately hydrolyzed by the ambient moisture to form a white solid compound, so that it is not accompanied by as great a risk of airway exposure as Et₄Pb.