Journal of Chromatography B, 988 (2015) 13–19 Contents lists available at ScienceDirect Journal of Chromatography B jou rn al hom ep age: www.elsevier.com/locate/chromb In vitro evaluation of Sun Protection Factor and stability of commercial sunscreens using mass spectrometry Diogo Noin de Oliveira 1 , Jeany Delafiori 1 , Mônica Siqueira Ferreira, Rodrigo Ramos Catharino * INNOVARE Biomarkers Laboratory, School of Pharmaceutical Sciences, University of Campinas, 13083-877 Campinas, São Paulo, Brazil a r t i c l e i n f o Article history: Received 22 September 2014 Accepted 9 February 2015 Available online 19 February 2015 Keywords: Sunscreens Sun Protection Factor Cosmetomics In vitro testing Bemotrizinol a b s t r a c t Sunlight exposure causes several types of injury to humans, especially on the skin; among the most common harmful effects due to ultraviolet (UV) exposure are erythema, pigmentation and lesions in DNA, which may lead to cancer. These long-term effects are minimized with the use of sunscreens, a class of cosmetic products that contains UV filters as the main component in the formulation; such molecules can absorb, reflect or diffuse UV rays, and can be used alone or as a combination to broaden the protection on different wavelengths. Currently, worldwide regulatory agencies define which ingredients and what quantities must be used in each country, and enforce companies to conduct tests that confirm the Sun Protection Factor (SPF) and the UVA (Ultraviolet A) factor. Standard SPF determination tests are currently conducted in vivo, using human subjects. In an industrial mindset, apart from economic and ethical reasons, the introduction of an in vitro method emerges as an interesting alternative by reducing risks associated to UV exposure on tests, as well as providing assertive analytical results. The present work aims to describe a novel methodology for SPF determination directly from sunscreen formulations using the previously described cosmetomics platform and mass spectrometry as the analytical methods of choice. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Skin is the organ that suffers the most extensive Sun exposi- tion in the human body; for that reason, it is also the most affected area when it comes to harmful effects, especially from ultraviolet (UV) radiation. Various endogenous protection mechanisms exist to help minimizing the hazard from chronic exposure; among oth- ers, stratum corneum, the outermost layer of the epidermis, is the most important one. Composed of keratin enucleated cells, it forms a thin barrier to prevent water loss and penetration of products from the environment, also assisting the reflection of only 5–10% of the light radiation [1]. Therefore, the use of sunscreens to minimize long-term effects has been strongly advised in the recent years, both by health organizations and as a result from scientific studies [2,3]. Sunscreens can form either physical [4] or chemical [5] bar- riers, depending on the chemical class of the components that are present in their formulations. In both cases, the involved * Corresponding author. Tel.: +55 19 3521 9138. E-mail address: rrc@fcm.unicamp.br (R.R. Catharino). 1 These authors contributed equally to this work. substances must have, respectively, the property to either physi- cally reflect – thus preventing the radiation passage – or absorb the UV radiation – usually by transferring energy through a conjugate  system of suitable organic molecules, such as the widely used bis-ethylhexyloxyphenol methoxyphenyl triazine (bemotrizinol) and ethylexyl triazone. Some filters, however, present low stability on in vitro assays when in contact with experimental UV radiation, which raises questions regarding the quality, safety and efficacy aspects of these products [6]. Current methodologies for Sun Protection Factor for UVA and UVB determinations follow either the standards from national stan- dardization organizations, as the United States Food and Drugs Administration (FDA) [12], or the International Standardisation Organisation (ISO) with the guidelines of ISO 24444:2010 and 24443:2012. The standard protocol for determination of the Sun Protection Factor (SPF) is performed by exposing areas of protected and unprotected volunteer human skin to artificial sunlight (ISO 24444:2010). The SPF is then defined as the ratio between the min- imal erythema dose (MED) in the sunscreen-protected skin and the MED of the unprotected skin. MED, in turn, is defined as the effective amount of energy, expressed in Joules/cm 2 , required to produce the first noticeable erythemal reaction with clearly defined edge, as per ISO 24444:2010. Alternatively, in vitro tests for UVB http://dx.doi.org/10.1016/j.jchromb.2015.02.018 1570-0232/© 2015 Elsevier B.V. All rights reserved.