| Acute, subchronic, and developmental toxicity and genotoxicity of 1,1,1-trifluoroethane (HFC-143a). | |
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MedLine Citation:
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PMID: 8789786 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The toxicity potential of 1,1,1-trifluoroethane (HFC-143a), a CFC alternative, was evaluated in several acute, subchronic, and developmental toxicity studies by the inhalation route and in genotoxicity studies. HFC-143a has a very low acute inhalation toxicity potential as shown by a 4-hr LC50 of > 540,000 ppm in rats. HFC-143A has a low potential to induce cardiac sensitization in experimental screening studies in dogs; only the highest concentration tested--300,000 ppm--elicited a cardiac sensitization response. In an initial 4-week nose-only inhalation study, male and female rats were exposed 6 hr/day, 5 days/week at concentrations of 0, 2000, 10,000, or 40,000 ppm. Females showed no evidence of toxicity at any exposure level; male rats did exhibit degenerative changes only in the tests at all exposure levels. However, because of exposure system irregularities, which resulted in excessive temperature conditions and stress in the HFC-143a-exposed groups, the study was repeated in male rats exposed by whole-body inhalation. In this repeat study no toxicity was observed at < or = 40,000 ppm. Moreover, a subsequent 90-day whole-body inhalation study in rats exposed 6 hr/day, 5 days/week at 0, 2000, 10,000, or 40,000 ppm resulted in no evidence of toxicity at any exposure concentration. The results of the second 4-week and the 90-day studies using whole-body exposures indicate that the findings from the first 4-week study were related to the stress induced by excessive temperatures and nose-only restraint. Therefore, the no-observed-effect level (NOEL) for rats repeatedly exposed up to 90 days was considered to be 40,000 ppm. In developmental toxicity studies with rats and rabbits, an increase in visceral variations or skeletal malformations was observed, respectively, at HFC-143a concentrations of 2000, 10,000 or 40,000 ppm (rat) or at the low and high concentrations (rabbit). Because of the unusually low control incidence of variations (1.6% per litter in the control versus 6.8-16.8% for historical control values), the lack of a clear dose-response relationship, and the lack of other developmental effects, these findings were not considered related to HFC-143a exposure. In addition, results from genotoxicity studies (Ames, chromosomal aberration with human lymphocytes, mouse micronucleus) demonstrated that HFC-143a was not mutagenic. |
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Authors:
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W J Brock; H J Trochimowicz; C H Farr; R J Millischer; G M Rusch |
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Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: Fundamental and applied toxicology : official journal of the Society of Toxicology Volume: 31 ISSN: 0272-0590 ISO Abbreviation: Fundam Appl Toxicol Publication Date: 1996 Jun |
Date Detail:
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Created Date: 1997-03-28 Completed Date: 1997-03-28 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8200838 Medline TA: Fundam Appl Toxicol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 200-9 Citation Subset: IM |
Affiliation:
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E. I. du Pont de Nemours & Co., Haskell Laboratory, Newark, Delaware 19714, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Abnormalities, Drug-Induced* Animals Dogs Dose-Response Relationship, Drug Escherichia coli / drug effects, genetics Female Heart / drug effects* Humans Hydrocarbons, Fluorinated / toxicity* Lymphocytes / drug effects Male Mice Mutagenicity Tests Mutagens / toxicity* Rabbits Rats Salmonella typhimurium / drug effects, genetics Toxicity Tests |
| Chemical | |
Reg. No./Substance:
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0/Hydrocarbons, Fluorinated; 0/Mutagens; 420-46-2/1,1,1-trifluoroethane |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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