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Life Sciences
Study results from Sapphire Group, Inc. provide new insights into life sciences
November 7th, 2009
Data detailed in 'Development of a physiologically based pharmacokinetic (PBPK) model for methyl iodide in rats, rabbits, and humans' have been presented. "Methyl iodide (MeI) has been proposed as an alternative to methyl bromide as a pre-plant soil fumigant that does not deplete stratospheric ozone. In inhalation toxicity studies performed in animals as part of the registration process, three effects have been identified that warrant consideration in developing toxicity reference values for human risk assessment: nasal lesions (rat), acute neurotoxicity (rat), and fetal loss (rabbit)," scientists in the United States report. "Uncertainties in the risk assessment can be reduced by using an internal measure of target tissue dose that is linked to the likely mode of action (MOA) for the toxicity of MeI, rather than the external exposure concentration. Physiologically based pharmacokinetic (PBPK) models have been developed for MeI and used to reduce uncertainties in the risk assessment extrapolations (e.g. interspecies, high to low dose, exposure scenario). PBPK model-derived human equivalent concentrations comparable to the animal study NOAELs (no observed adverse effect levels) for the endpoints of interest were developed for a 1-day, 24-hr exposure of bystanders or 8 hr/day exposure of workers," wrote L.M. Sweeney and colleagues, Sapphire Group, Inc. The researchers concluded: "Variability analyses of the PBPK models support application of uncertainty factors (UF) of approximately 2 for intrahuman pharmacokinetic variability for the nasal effects and acute neurotoxicity." Sweeney and colleagues published their study in Inhalation Toxicology (Development of a physiologically based pharmacokinetic (PBPK) model for methyl iodide in rats, rabbits, and humans. Inhalation Toxicology, 2009;21(6):552-82). For additional information, contact L.M. Sweeney, The Sapphire Group, Inc., Dayton, Ohio 45431 USA.. The publisher's contact information for the journal Inhalation Toxicology is: Taylor & Francis Group Ltd, 2 Park Square, Milton Park, Abingdon, Oxford OX14 4RN United Kingdom. Keywords: United States, Dayton, Life Sciences, Pharmacokinetics, Drugs, Therapies, Pharmaceuticals, Physiology. This article was prepared by NewsRx editors from staff and other reports. Copyright 2009, NewsRx.com.
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