Polyisobutene and Hydrogenated Polyisobutene are polymers. In cosmetics and personal care products, Polyisobutene and Hydrogenated Polyisobutene are used in the formulation of lipsticks, they can also be found in eye and facial makeup, skin care products and suntan products.
The Food and Drug Administration (FDA) has reviewed the safety of Polyisobutene (butyl rubber) and approved its use in chewing gum base. It is also approved as an indirect food additive for use in adhesives and polymers having incidental contact with food.
The safety of Polyisobutene and Hydrogenated Polyisobutene has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Polyisobutene and Hydrogenated Polyisobutene were safe for use in cosmetics and personal care products.CIR Safety Review: The CIR Expert Panel reviewed safety studies of these ingredients, as well as data on a related ingredient, Polybutene. The CIR Expert Panel previously determined that Polybutene was safe for use in cosmetics and personal care products.
Acute oral toxicity studies of high doses of these polymers demonstrated no effects other than lethargy. A 2-year chronic oral toxicity study of Polybutene revealed no gross or microscopic pathological changes, and no changes in body weights or food consumption, hematological values, urinalysis, or tumor formation that could be correlated with Polybutene ingestion. In another 2-year chronic oral toxicity study with Polybutene, no abnormalities in body weight, food consumption, survival, behavioral patterns, hematology, blood chemistry, urinalysis, liver function, gross and histopathological examinations, or organ weights were reported. In a
Neither Polyisobutene nor Hydrogenated Polyisobutene were ocular irritants, nor were they dermal irritants or sensitizers. Polyisobutene was not comedogenic. Polyisobutene did not induce transformation of cells. In a carcinogenicity study, Polyisobutene was not carcinogenic, nor did it promote the carcinogenicity of 7,12-dimethylbenz(alpha)anthracene.
Clinical patch tests showed no evidence of dermal irritation and repeat insult patch tests with a product containing 4% Hydrogenated Polyisobutene or 1.44% Hydrogenated Polyisobutene showed no evidence of sensitization. These products also were not phototoxic or photoallergenic. The product containing 4% Hydrogenated Polyisobutene was not an ocular irritant in a clinical test.
The octanol water partition coefficients of Polyisobutene and Hydrogenated Polyisobutene and their low water solubility suggested low dermal absorption (if any). Gastrointestinal absorption was also considered to be of no concern due to the low solubility of these chemicals. The CIR Expert Panel concluded that these large, mostly insoluble polymers were safe for use in cosmtics.
Link to the FDA Code of Federal Regulations for Butyl rubber
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRS...
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRS...
Polyisobutene and Hydrogenated Polyisobutene may be used in cosmetics and personal care products marketed in the European Union according to the general provisions of the Cosmetics Directive.
Link to the EU Cosmetics Directive:
http://ec.europa.eu/enterprise/cosmetics/html/consolidated_d...
