CIEnP offers a comprehensive package of assays to evaluate cosmetic ingredients for their in vitro efficacy and safety. Relatively simple one-cell type monolayer based test methods present a good and cost-efficient starting point. Most cosmetic formulation ingredients will come in contact with skin keratinocytes, melanocytes and possibly fibroblasts; therefore all cell types have been established as common in vitro test systems.

Cytotoxicity tests assess the skin irritation potential on cultured human or mammalian cell lines (OECD 129 and ISO 10993-5). Cytotoxicity is the first test to provide reliable insight into the safety of cosmetics and chemicals. Toxic effects on the cellular level could be identified by different viability tests including:

  • Neutral Red Uptake (NRU)
  • MTT Assay
  • Annexin V (apoptosis)
  • 7-AAD (necrosis)

In vitro efficacy assays to develop cosmetics could be performed in cell lines present on human skin, such as fibroblasts, keratinocytes or melanocytes. Furthermore, in vitro assay can be realized in non-cellular system to analyses antioxidant activity, enzyme activators or inhibitors, among others. These assays can help the sponsor to take an effective decision according to the strategy of the company.



  • Determination of hyaluronic acid and hyaluronidase activity
  • Aquaporin expression

Calming effect

Skin repair

Anti-oxidant effect


Skin pigmentation


  • Western blot
  • Real time PCR
  • Colorimetric assays
  • Enzyme assays
  • Immunocytochemistry
  • Immunofluorescence
  • Flow cytometry

The in vitro release test (IVRT) of drug/cosmetic active consists of an evaluation of the active principle release from a topical formulation using a Vertical Diffusion System (Franz Cell) equipped with a suitable synthetic membrane. This test is often used to ensure the quality and performance of the product over time and/or in the presence of changes in the production process. It is carried out according to the FDA guide: FDA Guidance for Industry: Nonsterile Semisolid Dosage Forms; Scale-Up and Postapproval Changes: Chemistry, Manufacturing, and Controls; In Vitro Release Testing and In Vivo Bioequivalence Documentation, May 1997.

It is the assessment of cutaneous absorption after topical exposure of drugs/cosmetic actives or finished products (medicines or cosmetics). The cutaneous absorption test in CIEnP is performed on fragments of human skin using a Vertical Diffusion System (Franz cell). The skin absorption test can be performed with different pharmaceutical presentations, such as liquid, solid and semi-solid. The test is performed according to OECD International Guide No. 428 and the supply and use of human tissue are fully in line with national ethical guidelines.

In vitro skin permeation using a Vertical Diffusion System (Franz cell)