National Toxicology Program

National Toxicology Program
http://ntp.niehs.nih.gov/go/ts-m88113

Testing Status of Isobutene - M88113

 

CASRN: 115-11-7

Formula: C4-H8

Synonyms/Common Names

  • 2-Methyl-1-propene

Known Uses

Production of diisobutylene, trimers, butyl rubber, antioxidants for foods, packaging, food supplements & plastics, isooctane, high-octane aviation gasoline. Polyisobutene resins. (NTP executive summary). Associated with tobacco: reported either as a natural component of tobacco, pyrolysis product (in tobacco smoke), or additive for one or more types of tobacco products.

Chemical Properties

Toxicity Effects (HSDB)

Short-Term Toxicity

  • 2 weeks (Inhalation)  (C88070)  Completed 
    • Rats: F344/N; Mice: B6C3F1
    • Dose: 4-DAY EXPOSURE, MAINTAIN ANIMALS FOR 1 WEEK FOLLOWING EXPOSURE. 0, 500, 1000, 2000, 4000, OR 8000 PPM (10/SEX/SPECIES/GROUP) 11 DAYS.
  • 13 weeks (Inhalation)  (C88070)  Completed 
    • Rats: F344/N; Mice: B6C3F1
    • Dose: R&M: 0, 500, 1000, 2000, 4000, OR 8000 PPM (10/SEX/SPECIES/GROUP).

Long-Term Carcinogenicity

  • 2 years (Inhalation)  (C88070)  Report Complete 
    • TR-487 (NIH Number: 99-3977)  (Peer Review Approval 12/10/1997A )
      Toxicology and Carcinogenesis Studies of Isobutene (CASRN 115-11-7) in F344/N Rats and B6C3F1 Mice (Inhalation Studies)
    • Rats: F344/N; Mice: B6C3F1
    • Carcinogenesis Results
      • Male Rats Some Evidence 
      • Female Rats No Evidence 
      • Male Mice No Evidence 
      • Female Mice No Evidence 
    • Dose: R&M: 0, 500, 2000, OR 8000 PPM (50/SEX/SPECIES/GROUP).

Special Studies

  • Absorption Disposition Metabolism Elimination (Inhalation)  (S0137)  Completed 
    • Citation: Henderson RF, Sabourin PJ, Bechtold WE, Steinberg B, Chang IY. Disposition of inhaled isobutene in F344/N rats. Toxicol Appl Pharmacol. 1993 Nov;123(1):50-61. Erratum in: Toxicol Appl Pharmacol 1994 Apr;125(2):333.Pubmed Abstract
    • Male Rats: F344/N

Genetic Toxicology

  • Micronucleus  (A91962)  Completed 
    • Mice: B6C3F1
    • Male Negative 
    • Female Negative 
  • Salmonella  (295184)  Completed 
    •  Negative 
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.