Evaluation of ingredients for topical specific applications: an in vitro tolerance approach

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  • June 20, 2018
  • 2 mins of read time

Evaluation of ingredients for topical specific applications: an in vitro tolerance approach

Alice Denis, Mickael Puginier, Catherine Bulcourt, Alicia Roso, Mathilde Bergal
2018, Skin Forum annual meeting

In vitro reconstructed human tissue models are recognized as being sensitive and reliable modelsto replace or reduce laboratory animal use in preclinical studies1,2. Dermo-pharmaceutical products target different body areas such as mucous membranes, healthy and damaged skin. The purpose of this work was to develop a new and predictive in vitro experimental approach in order to screen epithelia tolerance of ingredients, within the pharmaceutical development stage. Several 3D reconstructed models have been investigated. Among them, gingival and vaginal mucosa and injured skin were selected as relevant tools to widen our ingredients to new therapeutic applications (initially developed only for healthy skin). For mucosa, ingredients were applied at usual doses onto standard in vitro 3D models, for an increasing period of time.

Cellular viability measurement (MTT test) led to irritation potential conclusion according to supplier recommendations. For damaged skin, an innovative 3D Reconstructed human Epidermis model (RhE) with a physically impaired barrier function was developed (reproducible mechanical superficial abrasion at stratum corneum level). The skin tolerance was determined by (1) cellular viability (MTT test); (2) barrier function (TEER measurement and Biotin permeability); and (3) morphological evaluation (Hematoxylin Eosin Staining). Ingredients with different chemical structures and functionalities were tested and compared to negative control. Model predictivity was challenged with short chain surfactants including Sodium Dodecyl Sulfate (positive controls) as well as benchmarks.

This approach allows selection of suitable ingredients for each external body area. Moreover, it helps to determine the well-tolerated doses of emulsifiers and thickeners, pillars of topical pharmaceutical formulations. The Multiple Endpoints Analysis (MEA)3 designed for injured epidermis model enrichs basic irritation information with cellular, morphological and functional effects evaluation, thus enabling to appreciate not only the toxicity but also to identify some infraclinical reactions. MEA opens perspectives of new experimental models.

[1] Alépée et al., State-of-the-Art of 3D Cultures (Organs-on-a-Chip) in Safety Testing and Pathophysiology Altex 31, 4/14, 441-477, 2014. [2] Gordon S. et al., Non-Animal Models of Epithelial Barriers (Skin, Intestine and Lung) in Research, Industrial Applications and Regulatory Toxicology Altex 32(4), 327-378, 2015. [3] Meloni, M. et al., The importance of multiple endpoint analysis (MEA) using reconstituted human tissue models for irritation and biocompatibility assay. Invitox Congress Proceedings 4, 7, 2002.

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