The goal of this project is to provide support of National Toxicology Program (NTP) hazard identification activities targeted toward the prevention of diseases or adverse effects caused by environmental exposure to chemical or physical agents. Toxicity testing is an important aspect of public health research in that it serves to identify chemicals that are hazardous to human health. Proper chemical analyses are required to ensure that, in toxicity studies, the test species are exposed to the prescribed chemicals at the specified dose concentrations. This contract contributes to the ability of toxicity studies to provide evidence of heightened cancer risk along with other toxicological outcomes, by providing characterization of the chemicals studied, confirmation of the dose levels administered, and internal dose determinations. This information is critical to evaluation of toxicity tests and development of sound, scientific conclusions about the potential toxicity of the study chemical in the test species and ultimately supports the risk assessment efforts of National Toxicology Program and other federal agencies. With internal dose information provided by this contract, extrapolations to humans can be made so that the public can be adequately informed about risk factors arising from exposure to studied chemicals. During FY09, more than 180 tasks were begun, performed, and/or completed in support of NTP and DIR research and testing protocols. In support of an NTP dietary zinc study, the chemical composition and crystalline structure of zinc carbonate basic ([ZnCO3]2?[Zn(OH)2]3) was determined using X-ray diffraction, X-ray fluorescence, Thermogravimetric analysis, inductively-coupled plasma optical emission spectroscopy, and Fourier transform infrared spectroscopy. The material was found to be a mixture of zinc carbonate basic and zinc oxide with trace amounts of Mg and Ca, containing a small amount of water. In support of NTP reproductive toxicity studies, 15 phthalates were procured and comprehensively characterized using ultra high performance liquid chromatography (UPLC), gas chromatography, elemental analysis, and infrared spectroscopy. Dose formulation and dose analysis methods were developed and validated for 2 of these phthalates in two different feed vehicles. In support of planned NTP perinatal toxicity studies, a preliminary toxicokinetic study was performed for resveratrol administered to male and female, and timed pregnant female Wistar-Han rats. 24-hour urine was collected along with an 8-hour time-course in blood. These studies were designed to determine the major metabolites present after dosing to facilitate development of analytical methods targeting the parent and metabolites for future analysis of samples from the NTP studies. A small metabanomics study was conducted to look for changes in metabolite profile as a consequence of pregnancy and/or dosing. In support of an NIEHS study conducted by Dr. Freya Kamel, 450 samples from the study were analyzed for a suite of metals including lead and arsenic. To support NTP inhalation studies of butter flavored food additives a commercial ?recipe? for butter flavoring was obtained. The components of the commercial mixture were procured and individually characterized using a UPLC method. The butter flavoring mixture was then prepared according to the recipe and used to develop analysis methods and dosing protocols for the mixture. A separate collaboration with the National Cancer Institute and the Environmental Protection agency to extract potentially mutagenic substances from human urine samples and test the resulting extracts for mutagenicity using an assay developed by the EPA was completed. The chemistry support contractor continued characterization of 257 chemicals for the NTP high throughput toxicology screening initiative, using a gas chromatography rapid purity screen developed by the contractor. DMSO solubility predictors based on physical properties of the chemicals (i.e., Log P value), developed using training sets of chemicals used in the NTP 1408 set1 plate were used select chemical candidates for the NTP 1408 set2 plate being developed for the next phase of high-throughput testing.
