skin penetration 

Charles River has been performing in vitro skin penetration studies with human skin for more than 20 years. Human skin is obtained locally from elective plastic surgery with Ethics Committee approval and fully informed patient consent. We have both dynamic (flow through) and static (Franz type) cells.

Tests are performed using radiolabelled as well as non-radiolabelled analytical techniques. Studies are designed to reflect occupational exposure and uses of the test article in the formulation. They are designed and conducted to comply with OECD Test Guidance Document No. 28, and any relevant industry documents are also taken into consideration.

Skin from standard laboratory and livestock species can also be evaluated using the same methods. These data can be compared with the human data for risk assessment or between species comparison requirements and utilized to design dermal ADME/toxicology studies.

Both the dynamic flow through and static cell systems have been adapted to include a semi-occlusive graphite filter for use with volatile test articles to ensure maximum recoveries where appropriate.

A wide variety of materials from chemical, biocide and agrochemical industries can be evaluated in a range of different test preparations.  These include solids, liquids, solvents, gels and paints, and include radiolabelled as well as non-radiolabelled analytical techniques.

Episkin^® Irritation and Corrosivity

The SkinEthic Episkin^® model is used for the in vitro assessment of skin irritation according to OECD Test Guideline 439. At Charles River, we have successfully validated this model using a panel of recommended compounds (three irritants and five non-irritants). Cell viability is used to assess any resulting damage.

The same model is used for corrosivity testing according to OECD Test Guideline 431 and has been validated to evaluate the corrosive potential of chemicals.

HCE Eye Irritation

The SkinEthic HCE model is a reconstructed model of human corneal epithelium, reconstructed from the HCE cell line. In the HCE eye irritation assay, test item is applied to the upper surface of the epithelium for three minutes, then rinsed off and the cells are incubated for 16 hours to allow recovery or development of damage. At the end of this period, damage is assessed by measuring the cell viability (MTT assay) and histological examination. This assay is designed to classify substances as irritant (EU R41 or R36) or non-irritant.

For more information about our skin penetration studies, contact us at askcharlesriver@crl.com.