Polyisobutene is used medicinally in drug-release transdermal patches (1).

A variant of Polyisobutene, hydrogenated Plyisobutene (HP) is used for topical use in cosmetics as an emollient to hydrate and give the skin a pleasant feeling (2).

A 2-year chronic oral toxicity study of polybutene did not reveal macroscopic or microscopic pathological changes, so the CIR Experts Group does not believe that these mostly insoluble polymers present possible risks in the use practices and concentration described in this safety assessment (3).

References_____________________________

(1) Influence of adsorbents in transdermal matrix patches on the release and the physical state of ethinyl estradiol and levonorgestrel.
Schulz M, Fussnegger B, Bodmeier R.
Eur J Pharm Biopharm. 2011 Feb;77(2):240-8. doi: 10.1016/j.ejpb.2010.11.011.

Drug release and adhesive properties of crospovidone-containing matrix patches based on polyisobutene and acrylic adhesives.
Schulz M, Fussnegger B, Bodmeier R.
Eur J Pharm Sci. 2010 Dec 23;41(5):675-84. doi: 10.1016/j.ejps.2010.09.011.

(2) Skin moisturization by hydrogenated polyisobutene--quantitative and visual evaluation.
Dayan N, Sivalenka R, Chase J.
J Cosmet Sci. 2009 Jan-Feb;60(1):15-24.

(3) Final report of the cosmetic ingredient review expert panel on the safety assessment of Polyisobutene and Hydrogenated Polyisobutene as used in cosmetics.
[No authors listed]
Int J Toxicol. 2008;27 Suppl 4:83-106. doi: 10.1080/10915810802550611.

Polyisobutene is a chemical compound, a homopolymer of isobutene and has the function of improving the release of medicines or binding agent, film-forming and non-aqueous viscosity agent in cosmetic products.

Polyisobutene studies

Molecular Formula: C₄H₈  CH₂=C(CH₃)₂

Molecular Weight: 56.108 g/mol

CAS: 115-11-7

UNII: QA2LMR467H

EC Number: 204-066-3

PubChem Substance ID 24857786

MDL number MFCD00008898

Beilstein Registry Number 773645

Synonyms:

• 2-Methylpropene
• isobutene
• isobutylene
• 1-Propene, 2-methyl-
• 2-Methyl-1-propene
• 1,1-Dimethylethylene
• Isopropylidenemethylene
• 2-methylprop-1-ene
• Methylpropene
• gamma-Butylene
• Propene, 2-methyl-
• Polyisobutylene, chlorinated
• Isobuten
• iso-butylene
• .gamma.-Butylene
• 1-Propene, 2-methyl-, homopolymer, chlorinated
• 2-methyl-l-propene
• 2-methyl-2 propene
• iso-C4H8
• 2-MethylpropyleneMethylpropene2-Methylprop-1-ene
• 1,1-Dimethylethene
• InChI=1/C4H8/c1-4(2)3/h1H2,2-3H
• iso-butene
• sym-Dimethylethylene