Percutaneous Absorption
One of the primary roles of the skin is to form a barrier to protect humans from substances contacted in the environment. Permeation of a substance through the skin depends upon a number of factors, including: area of contact; duration of exposure; lipophilicity (fat solubility), molecular weight, and concentration of the test substance; and integrity of the stratum corneum and thickness of the epidermis. The qualities of the outermost layers of the skin, the stratum corneum, typically determine the rate of dermal penetration.
Dermal penetration testing, also know as percutaneous absorption, measures the absorption or penetration of a substance through the skin barrier and into the skin. Percutaneous absorption studies are conducted to determine how much of a chemical penetrates the skin, and thereby whether it has the potential to be absorbed into the systemic circulation. Dermal penetration is considered to occur by passive diffusion; however, biotransformation of the test substance within the skin (metabolism) prior to systemic absorption can occur.
CeeTox offers an in vitro screen for testing the percutaneous absorption of chemicals and cosmetics/personal care products. The in vitro test measures the permeability of a test substance through a multi-layered reconstructed human epidermis (RHE) model.
The screen determines relative flux rates, transdermal permeability, cytotoxicity, and metabolic stability of different compounds or different formulations of the same compound after topical application.
Donor solutions, aliquots of all time points taken, tissue rinsates, and tissue extracts will be analyzed for parent test compound and metabolites using appropriate chromatographic (HPLC, LC/MS) or radiometric (liquid scintillation counting) methodology. Assays performed include: Solubility analysis, Active Pharmaceutical Ingredient (API) Analysis, and MTT. Standard time points are 16 for API and 1 for MTT.
Let CeeTox scientists become an extension of your R&D team when we put our 10+ years of experience to work for you interpreting the data that enables you to make the best decisions and bring safer products to market faster and at lower cost.
To discuss your upcoming study, please call 269-353-5555 or email us at info@ceetox.com for more information and a personalized consultation.
Literature cited:
OECD. Guidance Document for the Conduct of Skin Absorption Studies. OECD Series on Testing and Assessment. No. 28. OECD. Paris, France.
http://www.alttox.org/ttrc/toxicity-tests/dermal-penetration/
ECVAM. Biokinetics. Altern. Lab. Anim. 30, suppl. 1, 56-57.