CD09 Acrylate co-polymers: no cause for concern

Abstract

Abstract Acrylate co-polymers are frequently used ingredients, believed to have low allergenic potential, present in a wide range of cosmetics, including skincare products, hairspray and nail varnish. Concerns have been expressed that individuals who are sensitized to (meth)acrylate monomers in ultraviolet (UV)-cured nail products may suffer elicitation reactions due to subsequent exposure to residual monomer impurities in acrylate co-polymers. The British Society for Cutaneous Allergy (BSCA) and the Cosmetic, Toiletry and Perfumery Association collaborated to investigate the allergenic potential of acrylate co-polymers. The BSCA prospectively audited data between 1 September 2021 and 1 September 2022 from the clinical databases of 20 patch test centres in the UK and Ireland, assessing the frequency of sensitization to three acrylate co-polymers. Patients with suspected or known allergy to (meth)acrylates and with facial dermatitis or (in some units) consecutive patients were tested to glyceryl acrylate/acrylic acid co-polymer 10% aqueous (aq.) (Lubrajel PF; United Guardian, Hauppauge, NY, USA), sodium polyacrylate 2% aq. (Cosmedia SP; BASF, Ludwigshafen, Germany) and EDT acrylates/C10-30 alkyl acrylate cross-polymer 2% aq. (Carbopol® ETD 2020 polymer; Lubrizol Advanced Materials, Wickliffe, OH, USA). During their manufacture, the pH of the patch test preparations was adjusted to within a range of 5.5–6.5. The antimicrobial preservative in the acrylate co-polymer patch test preparations, phenoxyethanol 1% aq. (Chemotechnique, Vellinge, Sweden), was also tested. Readings were carried out on days 2 and 4. The frequency of positive (1+/2+/3+), irritant and doubtful reactions was recorded. In total, 1302 patients were patch tested to the acrylate co-polymers. Of these, 335 were tested in addition to the (meth)acrylate series, 423 in addition to the facial and (meth)acrylate series and 277 in addition to the facial series and 267 were consecutively tested in addition to the baseline series. To glyceryl acrylate/acrylic acid co-polymer, there was one doubtful reaction in a patient allergic to multiple (meth)acrylates and one irritant reaction. To sodium polyacrylate, there were four irritant reactions, one doubtful reaction and one 1+ reaction; in all cases, relevance was unknown and there was no demonstrable (meth)acrylate allergy. There were no positive reactions to EDT acrylates/C10-30 alkyl acrylate cross-polymer. There was one irritant reaction to phenoxyethanol. In patients with positive patch test reactions to any (meth)acrylate (n = 67), there was no positive patch test to any acrylate co-polymer. Sensitization to these concentrations of acrylate co-polymers is rare. It is not possible to attribute dermatitis in (meth)acrylate-sensitized patients to a cosmetic ingredient with an International Nomenclature Cosmetic Ingredient name containing ‘acrylate co-polymer’.