PROVITAMIN TO C AND E IN SKIN 339 (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) M. A. Kassem, A. A. Kassem, and H. O. Aremar, Studies on the stability of injectable L-ascorbic acid solutions, Pharm. Acta Helv., 44, 611-623 (1969). Y. W. Chien, Logics of transdermal controlled drug administration, Drug Dev. & Ind. Pharm., 9, 497-520 (1983). J. Shaw, Development of transdermal therapeutic systems, Drug Dev. & Ind, Pharm., 9, 579-604 (1983). W. I. Higuchi, N. A. Gordon, J. L. Fox, and N. F. H. Ho, Tarnsdermal delivery of prodrugs, Drug Dev. & Ind. Pharm., 9, 691-706 (1983). Y. Ishida, Action of vitamin C and its derivatives, FragranceJ. (Japan), 63, 28-34 (1983). T. Nisiyama, M. Naganuma, Y. Fujinuma, and K. Nakajima, Studies on the percutaneous absorp- tion and the skin metabolism of ascorbic acid 2-sulfate in guinea pigs, Vitamins (Japan), 56, 537-542 (1982). T. Shiratori, Uptake, storage and excretion of chylomicra-bound 3H-a-tocopherol by the skin of the rat, Life Sciences, 14, 929-935 (1974). K. Tojo, J. A. Masi, and Y. W. Chien, Hydrodynamic characteristics of an in vitro drug permeation cell, I&EC Fundamentals, 24, 368-373 (1985). K. H. Valia, K. Tojo, and Y. W. Chien, Long term permeation kinetics of estradiol: (III) Kinetic analyses of the simultaneous skin permeation and bioconversion of estradiol esters, Drug Dev. Ind. Pharm., 11, 1133-1173 (1985). Y. Miura, Histochemical studies on enzyme activities in the skin, J. Dermatol. Japan (in Japanese), 74, 556-570 (1964). B. D. Bunday, in Basic Optimisation Method (Edward Arnold Pub., 1984), Part 4, pp. 47-76. E. Ginter and P. Bobek, in Vitamin C, J. N. Counsell and D. H. Hornig Eds. (Applied Science Publishers, Englewood, NJ, 1981), pp. 299-347.