LC-MS/MS method for the determination of melamine in rat plasma: toxicokinetic study in Sprague-Dawley rats.

Most recently, melamine has raised international concern for its catastrophic health effects stemming from tainted infant formula. So far there is limited information concerning the pharmacokinetics of melamine in mammals. The present report concerns the development and validation of a sensitive HPLC-ESI-MS/MS method for the pharmacokinetic study of melamine in rat. The method employed a simple liquid-liquid extraction process for plasma sample cleanup, and the extraction recoveries of melamine from plasma were consistent at different concentrations. There was a linear relationship between chromatographic area and concentration over the range of 10-5000 ng/mL for melamine in plasma (R = 0.995). In this work, for the first time, melamine was administered intravenously and orally to Sprague-Dawley rats and the pharmacokinetic characteristics of this contaminant were investigated. The mean values of major pharmacokinetic parameters of oral availability, the mean steady-state distribution volume (V(ss)), clearance, and plasma elimination half-life (T(1/2)) of melamine in Sprague-Dawley rats were 72.9 +/- 13.2%, 102.5 +/- 12.5 mL/kg, 20.1 +/- 3.8 mL/h/kg, and 4.9 +/- 0.5 h, respectively. The rats pharmacokinetic study results suggested that melamine was predominantly restricted to blood or extracellular fluid and is not extensively distributed to most organ tissues. Meanwhile, melamine should be primarily eliminated by renal filtration for rats and does not undergo significant metabolism. These data should be useful to regulatory for risk assessment.