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© 1988 Society of Cosmetic Chemists
Journal of the Society of Cosmetic Chemists, Vol. 39, No. 5, 275-281

Studies of the penetration of native collagen, collagen alpha chains, and collagen cyanogen bromide peptides through hairless mouse skin in vitro
Scott D. Coapman , J. Leon Lichtin , Adel Sakr , John R. Schiltz



Experiments are reported here which assessed the ability for radioactively-labeled native collagen, collagen alpha 1(I) chain subunits, and cyanogen bromide peptides derived from alpha 1(I) chains to penetrate hairless mouse skin mounted in percutaneous absorption cells. Sixty to 70% of the applied dose of radioactive label from [ 3 H]-propionylated collagen penetrated the epidermis of tape-stripped skin during a 48-hour period, whereas none of this material penetrated through control skin possessing intact stratum corneum. Dimethyl sulfoxide did not influence absorption in either type of skin preparation. In marked contrast, none of the radioactivity from [ 3 H]-proline-labeled collagen alpha chains (synthesized by 3T6 mouse fibroblasts) penetrated control or tape-stripped skin. These contradictory results likely result from epidermal-mediated removal of the labeled propionic acid from the collagen preparation, followed by diffusion of the label into the dermis. The evidence for this is based on the observation that all the radioactivity recovered in the receptor phase had a molecular weight less than 8,000 daltons, as shown by dialysis. Further experiments demonstrated that approximately 30% of the applied dose of [ 3 H]-amino acid-labeled cyanogen bromide collagen peptides penetrated tape-stripped skin, whereas control skin with intact stratum corneum did not allow passage.

We conclude from these experiments that native type I collagen, type I collagen alpha chain subunits, or type I collagen cyanogen bromide peptides do not penetrate intact mouse skin, although limited penetration of cyanogen feromide peptides does occur in skin lacking stratum corneum. Furthermore, experiments which purport to demonstrate penetration of native collagen using preparations labeled with radioactive ligands should be accompanied by demonstrations that the labeled material which penetrates into the dermis has been unchanged.

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© 1988 Society of Cosmetic Chemists
Journal of the Society of Cosmetic Chemists