Integration of in vivo and in vitro data for the evaluation of parabens in body cream

Description

Although literature studies have reported body burden of topical formulation ingredients, several controversies remain. Parabens are preservative ingredients widely used in personal care products (PCPs). Integrating in vitro transdermal permeation and biomonitoring studies provides an efficient approach to evaluating the safety or potential hazards associated with exposure to these ingredients. In this study, an experimental biomonitoring group comprising 20 women from Alfenas (aged 18–41 years) was evaluated by analyzing serum, oral fluid, and urine samples. Serving as their own experimental controls, participants applied a paraben-free body cream for 7 days, followed by a non-paraben-free body cream for an additional 7 days. Subsequently, transdermal permeation of the non-paraben-free body cream was evaluated as ex vivo using pig skin in a Franz-type vertical diffusion cell, with analyte quantification performed via high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). The analysis of internal dose bioindicators in urine was inconsistent with previous literature findings, whereas oral fluid samples were unrepresentative of the alterations observed in serum samples. In serum, statistically significant differences were observed between Phases 1, 2 and 3 (control and paraben-free body cream, respectively) compared with Phases 4 and 5 (non-paraben-free body cream) for methylparaben (MeP) (p-value= 9.39 × 10⁻¹¹) and propylparaben (PrP) (p-value = 1.66 × 10⁻¹¹). These results closely aligned with the ex vivo pig ear skin permeation data; following 6 h of exposure, approximately 70.65 μg/cm² of MeP permeated into the epidermis, while 10.4% was retained within the layer. Because over 71% of PrP remained retained in the skin, transdermal permeation could not be quantified using the present analytical methodology. Overall, this study demonstrates that cosmetic ingredients can undergo transdermal permeation following topical application of body cream, exceeding the safety margin threshold for allergic sensitization 21.9 μg/cm² established by the Handbook of Cosmeceutical Excipients. This finding is supported by the increased systemic exposure observed during short-term serum biomonitoring; however, further studies investigating the allergenicity of parabens are required.

Institutions

• Universidade Federal de Alfenas

  Minas Gerais, Alfenas

Categories

Funders

• Fundação de Amparo à Pesquisa do Estado de Minas Gerais

  Federal Government of Brazil

  Minas Gerais, Belo Horizonte
• Coordenação de Aperfeicoamento de Pessoal de Nível Superior

  Ministry of Education

  Federal District, Brasília

Licence