To aid this interpretation, a model of dermal absorption, partitioning, and degradation of methanol is developed and validated. The model includes stratum corneum, epidermis, blood, lung, body water, and urine compartments. Uptake into the skin is diffusion-limited. First order of metabolism of methanol is assumed. The model is evaluated using studies in which human subjects immerse a hand in methanol for periods ranging up to 16 minutes.
Methanol is measured in breath, blood, and urine before and after exposure.
The model reproduces features needed to interpret biological exposure indices for dermal exposures. Model and experimental results illustrate that during the period of dermal exposure, when the solvent is being taken up by the skin and subcutaneous tissue and diffused into the blood, arterial blood concentrations are approximately double venus blood concentrations. At the cessation of exposure, breath and arterial blood concentrations rapidly decline to an equilibrium between the major compartments of blood and body water. Causes a One-Year Persistence of Airway Sensitization, Demonstrable in Vivo and in Vitro. A clear understanding of causality can lead to more effective preventive measures.