Polyisobutene

What Is It?

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.

Why Is It Used?

Both Polyisobutene and Hydrogenated Polyisobutene increase the thickness of the lipidFat or fat-like substance found in the cells of plants and animals that includes fats, waxes, oils, and related compounds. (oil) portion of cosmetics and personal care products. Polyisobutene dries to form a thin coating on the skin, hair or nails, and is used to hold together the ingredients of a compressed cake. Hydrogenated Polyisobutene acts as a lubricant on the skin’s surface, which gives the skin a soft and smooth appearance.

Scientific Facts

Polyisobutene is often referred to as butyl rubber and is produced in a wide range of molecular weights; the lower molecular weight Polyisobutenes are very viscous, soft, and tacky semi-liquids while the higher molecular weight Polyisobutenes are tough and elastic rubbery solids. Hydrogenated Polyisobutene is also produced in a wide range of molecular weights and is widely used as a substitute for another cosmetic ingredient, squalene.

Safety Information

The Food and Drug Administration (FDA) has reviewed the safety of Polyisobutene (butyl rubber) and approved its use in chewing gumSticky, polysaccharide substances exuded by plants that are gelatinous when moist but harden on drying. base. It is also approved as an indirect food additiveIndirect food additives are additives that may become part of the food in trace amounts due to its packaging, storage or other handling. For example, minute amounts of packaging substances may find their way into foods during storage. 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 ReviewThe Cosmetic Ingredient Review (CIR) was established in 1976 as an independent safety review program for cosmetic ingredients. The CIR Expert Panel consists of independent experts in dermatology, toxicology, pharmacolgy and veterinary medicine. The CIR includes participation by the U.S. Food & Drug Administration and the Consumer Federation of America. (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 3-generation reproductive study of ingested Polybutene, there was no difference from controls in successive generations with regard to survival, weight gain, litter size, the number of stillborn, and the number of viable offspring during lactation.

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

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 Regulation.

Link to the EU Cosmetic Regulation:
http://europa.eu/legislation_summaries/consumers/product_labelling_and_p…

More Scientific Information

Polyisobutene and Hydrogenated Polyisobutene are homopolymers of isobutene. In cosmetics and personal care products, Polyisobutene is used as a binderIngredients that hold together the ingredients of a compressed tablet or cake., film formerIngredients that dry to form a thin coating on the skin, hair or nails. and viscosity increasing agent – nonaqueous. Hydrogenated Polyisobutene functions as a skin conditioning agent – emollient and a viscosity increasing agent – nonaqueous in cosmetics and personal care products.

Resources

Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging: http://www.fda.gov/Food/IngredientsPackagingLabeling/default.htm

Food Contact Substances: http://www.fda.gov/Food/IngredientsPackagingLabeling/PackagingFCS/defaul…

Substances Generally Recognized As Safe (GRAS“GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.): http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/default.htm

Search the Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm

EU Cosmetics Inventory http://ec.europa.eu/consumers/cosmetics/cosing/