Linked Life Data

11029265

Source:http://linkedlifedata.com/resource/pubmed/id/11029265

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-10-30
pubmed:abstractText
HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) are used to replace chlorofluorocarbons (CFCs) in refrigerant and aerosol applications, including medical use in metered-dose inhalers. Production and consumption of CFCs are being phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer. The safety and pharmacokinetics of HFC 134a and HFC 227 were assessed in two separate double-blind studies. Each HFC (hydrofluorocarbon) was administered via whole-body exposure as a vapor to eight (four male and four female) healthy volunteers. Volunteers were exposed, once weekly for 1 h, first to air and then to ascending concentrations of HFC (1000, 2000, 4000, and 8000 parts per million (ppm)), interspersed with a second air exposure and two CFC 12 (dichlorodifluoromethane) exposures (1000 and 4000 ppm). Comparison of either HFC 134a or HFC 227 to CFC 12 or air gave no clinically significant results for any of the measured laboratory parameters. There were no notable adverse events, there was no evidence of effects on the central nervous system, and there were no symptoms of upper respiratory tract irritation. HFC 134a, HFC 227, and CFC 12 blood concentrations increased rapidly and in an exposure-concentration-dependent manner, although not strictly proportionally, and approached steady state. Maximum blood concentrations (C(max)) tended to be higher in males than females; in the HFC 227 study, these were statistically significantly (P < 0. 05) higher in males for each HFC 227 and CFC 12 exposure level. In the HFC 134a study, the gender difference in C(max) was only statistically significant (P < 0.05) for CFC 12 at 4000 ppm and HFC 134a at 8000 ppm. Following the end of exposure, blood concentrations declined rapidly, predominantly biphasically and independent of exposure concentration. For the HFC 134a study, the t(1/2)alpha (alpha elimination half-life) was short for both CFC 12 and HFC 134a (<11 min). The t(1/2)beta (beta elimination half-life) across all exposure concentrations was a mean of 36 and 42 min for CFC 12 and HFC 134a, respectively. Mean residence time (MRT) was an overall mean of 42 and 44 min for CFC 12 and HFC 134a, respectively. In the HFC 227 study, t(1/2)alpha for both CFC 12 and HFC 227, at each exposure level, was short (<9 min) and tended to be lower in males than females. For CFC 12 mean t(1/2)beta ranged from 23 to 43 min and for HFC 227 the mean range was 19-92 min. The values tended to be lower for females than males for HFC 227. For both CFC 12 and HFC 227, MRT was statistically significantly lower (P < 0.05) in males than females and independent of exposure concentration. For CFC 12, MRT was a mean of 37 and 45 min for males and females, respectively, and for HFC 227 MRT was a mean of 36 and 42 min, respectively. Exposure of healthy volunteers to exposure levels up to 8000 ppm HFC 134a, 8000 ppm HFC 227, and 4000 ppm CFC 12 did not result in any adverse effects on pulse, blood pressure, electrocardiogram, or lung function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0273-2300
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Academic Press.
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22-35
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11029265-Administration, Inhalation, pubmed-meshheading:11029265-Adult, pubmed-meshheading:11029265-Aerosol Propellants, pubmed-meshheading:11029265-Atmosphere Exposure Chambers, pubmed-meshheading:11029265-Blood Pressure, pubmed-meshheading:11029265-Chlorofluorocarbons, Methane, pubmed-meshheading:11029265-Dose-Response Relationship, Drug, pubmed-meshheading:11029265-Double-Blind Method, pubmed-meshheading:11029265-Electrocardiography, pubmed-meshheading:11029265-Female, pubmed-meshheading:11029265-Half-Life, pubmed-meshheading:11029265-Humans, pubmed-meshheading:11029265-Hydrocarbons, Fluorinated, pubmed-meshheading:11029265-Inhalation Exposure, pubmed-meshheading:11029265-Male, pubmed-meshheading:11029265-Respiratory Function Tests, pubmed-meshheading:11029265-Safety, pubmed-meshheading:11029265-Sex Characteristics
pubmed:year
2000
pubmed:articleTitle
Human safety and pharmacokinetics of the CFC alternative propellants HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) following whole-body exposure.
pubmed:affiliation
TNO Nutrition and Food Research Institute, Zeist, The Netherlands.
pubmed:publicationType
Journal Article, Clinical Trial, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't