Final Report of the Cosmetic Ingredient Review Expert Panel Amended Safety Assessment of Cellulose and Related Polymers as used in Cosmetics

An earlier safety assessment of several cellulose polymers has been expanded to include cellulose itself and other cellulose polymers used in cosmetics. In general, these ingredients are modified cellulose polymers formed by reaction with the free hydroxyl groups in cellulose. The number of hydroxyl groups reacting, as well as the nature of the substitute group, largely determine the physical properties, particularly solubility, of the product. These ingredients are used in a wide variety of cosmetics as thickeners, suspending agents, film formers, stabilizers, emulsifiers, emollients, binders, or water-retention agents. These ingredients do not appreciably penetrate the skin barrier. Cellulose and its polymers pass essentially unchanged through the gastrointestinal tract following oral administration and are practically non-toxic. Ocular and dermal irritation studies indicate, at most, minimal irritants and not sensitizers. These ingredients are considered safe as cosmetic ingredients in the practices of use and concentration given in this safety assessment. INTRODUCTION The Cosmetic Ingredient Review (CIR) Expert Panel evaluated the safety of Hydroxyethylcellulose, Hydroxypropylcellulose, Methylcellulose, Hydroxypropyl Methylcellulose, and Cellulose Gum as used in cosmetics, concluding that these ingredients are “safe as cosmetic ingredients in the present practices of use and concentration” (Elder 1986). The CIR Expert Panel has further considered other related ingredients and determined that the available data support the safety of cellulose and a larger group of modified cellulose polymers. Accordingly, the CIR Expert Panel is amending the original safety assessment (Elder 1986) to include other ingredients. Therefore, this report addresses the safety of: • Calcium Carboxymethyl Cellulose, • Carboxymethyl Cellulose Acetate Butyrate, • Carboxymethyl Hydroxyethylcellulose, • Cellulose, • Cellulose Acetate, • Cellulose Acetate Butyrate, • Cellulose Gum, • Cellulose Acetate Propionate, • Cellulose Acetate Propionate Carboxylate, • Cellulose Succinate, • Cetyl Hydroxyethylcellulose, • Ethylcellulose, • Hydrolyzed Cellulose Gum, • Hydroxybutyl Methylcellulose, • Hydroxyethylcellulose, • Hydroxyethyl Ethylcellulose, • Hydroxypropylcellulose, • Hydroxypropyl Methylcellulose, • Hydroxypropyl Methylcellulose Acetate/Succinate, • Methylcellulose, • Methyl Ethylcellulose, • Methyl Hydroxyethylcellulose, • Microcrystalline Cellulose, • Potassium Cellulose Succinate, and • Sodium Cellulose Sulfate. CHEMISTRY Definition and Structure The structure of cellulose is shown in Figure 1a. By comparison, the structure for Carboxymethyl Cellulose Acetate Butyrate as given in the International Cosmetic Ingredient Dictionary and Handbook (Gottachalck and Bailey 2008), where R represents hydrogen or the acetyl or butyryl moiety, is shown in Figure 1b. According to Hake and Rowe (1963), Hydroxyethylcellulose, Hydroxypropylcellulose, Methylcellulose, Hydroxypropyl Methylcellulose, and Cellulose Gum are modified cellulose polymers. These cellulose ethers are derived from the reaction of the three free hydroxyl groups in the 2-, 3-, and 6positions of the (a)