TRANSCUTANEOUS ABSORPTION OF VITAMIN A 181 to (1) vitamin A stored in livers and (2) vitamin A in skins. Values for vitamin A in both livers and skins were calculated and evaluated as units per total weight of these tissues. Both groups of rats exhibited the three experimental findings which are indicative of systemic effects of vitamin A, viz.: applied to skin and to the vitamin administered by mouth. In proportion to amounts of vita- min A stored in livers, the rats receiving topical applications of the vitamin exhibited greater gains in weight than did the animals fed vitamin A. The coefficients of correlation between these two sys- temic effects of vitamin A were 0.71 TABLE 4•CoMPARATIVE AMOUNTS OF VITAMIN A IN SKINS AND LIVERS OF RATS RECEIVINO THE VITAMIN EITHER OKALL¾ OK IN TOPICAL APPLICATIONS TO SKINS No. Av. Body of Wt., Gin. Groups Rats Initial Final Vitamin A fed orally 14 115 144 Vitamin A applied to 14 116 144 skins Units of Vitamin A per Wt. of Tissues Skin-- Max. Min. Mean 3.5 Trace 1.6 5.8 Trace 2.7 ,Liver-- Max. Min. Mean 81 6 36.3 63 Trace 32.4 1. Gains in weight. 2. Levels of vitamin A in livers and skins above levels of de- pleted rats and negative con- trols (Table 1). 3. No evidence of metaplasia of specialized epithelial tissues, e.g., keratosis of the urinary tract, xerophthalmia, and lo- calized infections. Results of the comparative series of experiments summarized in Table 4, as well as those presented in Chart I and Table 3 are conclusive evi- dences of the transcutaneous ab- sorption of vitamin A from the petrolatum base applied to the rats' skins. The data summarized in Table 4 reveal some differences between the responses of the rats to vitamin A for the 14 rats receiving topical applications of vitamin A and 0.36 for the 14 rats fed the vitamin. Also, the rats to which vitamin A was applied topically showed larger amounts of vitamin in their skins, both ventral and dorsal, than did the animals receiving oral doses of the vitamin. Between these two results, the former group gave a coefficient of correlation of 0.75 and the latter a coefficient of 0.69. CONCLUSION R.e,sults of both preventive and curative series of experiments pro- vide definite evidence of the trans- cutaneous absorption of vitamin A from a petrolatum base applied to rats' skins. The findings of a small group of curative experiments suggested that

182 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS massage of the base over the skin enhances the transcutaneous ab- sorption of vitamin A. This hy- pothesis was supported by results of subsequent series of experiments in which vitamin A in skin cream bases was either spread or massaged over rats' skins. REFEKENCES (1) H. arty, R. G., "The Principles and Prac- tice ooe Modern Cosmetics. Volume One. Modern Cosmeticology," Leonard Hill Ltd. (1946), p. 74. (2) Pharma•copcela of the United States, 11th Edition (1936), p. 280. (3) Cart, F. H., and Price, E. A., Bioehem. y., 20, 497 (1926). (4) Morton, R. A., "Absorption Spectra of Vitamins and Hormones," Adam Hilger, Ltd., London, p. 17. (5) Pharmacopceia of the United States, 11th Edition (1936), p. 478. (6) Baumann, C. A., Riising, B. M., and Steenbock, H., Y. Biol. Chem., 107, 705 (1934). (7) McCoord, A. B., and Luce-Clausen,'E. M., .% Nutrition, 7, 557 (1934). (8) Clausen, S. W., and McCoord, A. B., Proe. •lm. $oe. Biol. Chemists, 1, 105 (1942). Back issues of THE JOURNAl. or THE SOCZET¾ Or COSMETIC CHEMZSTS can be obtained at $1.50 per copy. The following issues are available-- Vol. I, No. lqJuly, 1947 Vol. I, No. 2--March, 1948 Address your orders, with check to cover, to the Publication Office. '