Jones, B.C., H. A. Raabe, A. Sizemore, G.C. Mun, E.H. Theophilus and M.S. Dickens. (2000). Lack of Phototoxicity of Cosmetic Formulations Containing Glycolic Acid in An In Vitro Human Skin Model. The Toxicologist. 54(1). Abstract # 1853.

glycolic acid - 00079-14-1; octyl methoxycinnamate - 05466-77-3; chlorpromazine - 00050-53-3

Glycolic acid (GA) is a naturally occurring product found in sugar cane and is a member of a class of chemicals known as alpha-hydroxy acids. GA has been widely used in cosmetic and dermatological formulations for over a decade. These formulations are often used in dermal applications where they may be subject to ultraviolet radiation (UV) exposure from sunlight. We have investigated the potential for phototoxicity of typical cosmetic concentrations of GA (4% and 8%) in a generic cosmetic formulation with and without a chemical sunscreen (octyl methoxycinnamate, SPF2). The assays were conducted following a cytotoxicity protocol using a human keratinocyte model, EpiDerm (tm) (Epi-200), utilizing a colorimetric thiazolyl blue (MTT) endpoint. Prior to formulation exposure, a maximum non-cytotoxic dose in EpiDerm was established for UVA/B radiation (290-400 nm) utilizing a metal halide lamp solar simulator. The maximal dose of UVA/B radiation that caused negligible cytotoxic effects was 1.35/0.135 J/cm2 UVA/UVB, respectively. The maximal exposure for UVA treatment alone (320-40 nm) was 6 J/cm2. For subsequent assays, EpiDerm cultures were treated with the maximal non-cytotoxic dose of UVA/B or UVA. EpiDerm cultures were exposed to test materials or controls (negative control, vehicle, positive control, chlorpromazine) for two hours prior to UV exposure and returned to the incubator (0-45 hours) after exposure, followed by MTT cytotoxicity analysis. GA treated tissues exposed to UV showed relative survival percentages comparable to tissues that received no UV (89-109%); positive phototoxic control showed an expected cytotoxic response (7.5%). These studies indicate that glycolic acid contained in these cosmetic formulations is not phototoxic after UVA/B or UVA exposure and can be used in dermal cosmetic applications where UV radiation exposure may occur.