Human Inhalation of Halon 1301, HFC-134a and HFC-227ea for Collection of Pharmacokinetic Data.
Interim rept. Jan-Aug 97,
MANTECH ENVIRONMENTAL TECHNOLOGY INC DAYTON OH
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International agreement and regulatory decisions have driven activities to replace ozone depleting chemicals ODCs in fire suppression and refrigeration applications. In order to validate a human physiologically based pharmacokinetic model designed for use in estimating chemical biodistribution and establishing egress times, human volunteers were exposed via inhalation to a series of chemicals relevant to ODC replacement activity. Seven male volunteers ranging from 21-49 years of age were selected to inhale bromotrifluoromethane Halon 1301 0.5, 1,1,1,2-tetrafluoroethane HFC-134a, 0.4 and 1,1,1,2,3,3,3-heptafluoropropane HFC-227ea, 0.6. Each inhalation exposure was to a single chemical and was scheduled to last 30 minutes. Inhaled concentration and end alveolar expired concentration of chemical were continuously measured throughout the procedure using a non-rebreathing valve inhalation apparatus and a mass spectrometer. Blood samples were drawn through an indwelling cannula at times 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 10, 15, 20, 25 and 30 minutes during the exposure and for five minutes at one minute intervals following the inhalation. The blood was analyzed for the chemical of interest to determine the chemical time course in blood. Throughout the exposure period, human subjects were monitored via ECG, blood pressure and pulse rate measurements. All seven volunteers completed the Halon 1301 exposures without effect on ECG, blood pressure or pulse rate. Halon 1301 concentrations in blood at exposure termination ranged from 0.19-1.24 mgL. The HFC-134a and HFC-227ea exposures were terminated for safety reasons following unexpected and uncontrollable rapid rises in pulse rate during the inhalation exposure.
- Safety Engineering