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Compositions on natural nails mostly contain acrylic monomers, more often 2-hydroxyethyl methacrylate (HEMA). These systems have been considered to be a potent sensitizer in contact with the skin. The purpose of the study was to compare five acrylic monomers: HEMA (hydroxyethyl methacrylate), HPMA (hydroxypropyl methacrylate), IBOMA (isobornyl methacrylate), MEP (methacryloylethylphosphate) and TMPTMA (trimethylpropane trimethacrylate) to find the substitute to HEMA. In this study, we explored the rheological and polymerization properties of uncured systems containing five acrylate monomers. Mechanical and adhesion properties were evaluated of cured compositions. Optimal criteria of compositions and cured coatings were defined, and tests were performed to find the most appropriate composition. HEMA is the most widely used acrylic monomer in nail coatings due to its outstanding characteristics: high reactivity (temperature reached at polymerization Tmax = 95 °C), good adhesion (1.5 MPa on glass and aluminum), high solubility in acetone (ms = 22 %). The greatest potential to substitute HEMA has monomer HPMA, due to its good abrasion resistance (G = 66 GU after abrasion), high reactivity (Tmax = 88 °C), and adhesion (1.5 MPa on glass and on aluminum). The polymerization process of a composition containing MEP was the fastest and reached the highest maximum temperature during polymerization process (Tmax = 115 °C) and great adhesion (2.5 MPa). The best surface abrasion resistance (G = 76 GU after abrasion) was reached for coatings containing TMPTMA. [ABSTRACT FROM AUTHOR]

Individuals working in nail salons are exposed to 2-hydroxyethyl methacrylate (HEMA). HEMA has been found to have several effects on the skin: skin itching, peeling, redness and allergic contact dermatitis. The purpose of the study was to compare the effects of nail coatings containing HEMA and 2-hydroxypropyl methacrylate (HPMA) on the skin. In this study we explored the irritation properties of HEMA and HPMA containing nail coatings in cell cultures in-vitro and in skin PATCH tests under dermatological control. The cytotoxicity of coatings was tested in BALB/c3T3 and HaCaT cell lines by a neutral red uptake assay. Cytotoxicity was expressed as a concentration-dependent reduction of the uptake of neutral red, compared to the untreated controls. Open patch tests were supervised by a certified dermatologist. Polymerized coating extracts have little effect on Balb/c 3T3 cell viability, while having mild cytotoxic effects on HaCaT keratinocytes. Among two tested samples, extracts of HEMA containing coating exhibited higher cytotoxicity - reduction of keratinocyte viability by 28.29 % in case of undiluted 24 h extract and even by 48.26 % in case of 50 % extract was observed. Coating cytotoxiaty observed on HaCaT showed that the keratinocyte cell line was more sensitive to HEMA than to HPMA containing coating. [ABSTRACT FROM AUTHOR]

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