PERCUTANEOUS ABSORPTION OF VITAMIN A 369 EXPERIMENTAL METHOD, RESULTS, AND DISCUSSION Three-tenths gram of material containing vitamin A was applied daily to the skin in the scapular region of normal and vitamin A deficient rats, for a period of twenty-eight days in most cases. Details of the method of application are given elsewhere (5, 6). The criteria for the amount of absorption of the vitamin were: vitamin A content of the blood, liver and kidneys and histological changes of the skin. TABLE 2--TOPICAL APPLICATION OF VITAMIN A IN VARIOUS MEDIA TO "A"-DEPLE'rED RATS Mean age of litters at end of study--78 days. Duratien of study--28 days •A• Stores "A" Liver and Serum No. of Applied, Body Gain,* Kidney, "A," Media Animals /•g./Day wt., g. g. /•g./Total /•g. % D-ointment 3 30 86 20 3.4 9 L-ointment 3 30 89 23 3.5 26 L-ointment plus tocopherols 4 30 85 19 6.4 8 D-ointment-fortified 3 200 108 32 31.4 25 Oral corn oil 2 1 117 54 6.8 39 Oral corn oil 2 20 117 58 98.0 68 * Gain in body weight from time of depletion of vitamin A. TABLE 3--TOPICAL APPLICATION OF VITAMIN A IN VARIOUS MEDIA Mean age of litters at end of study--85 days. Duration of study--28 days "A" Stores "A" I,iver and No. of Applied, Body Kidney, Serum Media Animals /•g./Day wt., g. Gain,* g. /•g./Total "A,"/•g. % D-lotiont 6 10 150 31 8.1 46 D-ointment 6 30 138 44 11.2 14 E-ointment 6 175 138 38 169 62 Oral corn oil 3 I 175 47 15.0 30 * Gain in body weight from time of depletion of vitamin A. • Fresh bottle of D-lotion used every two days. TABLE 4--THE INFLUENCE OF MEDIA UPON THE PERCUTANEOUS AND ORAL ABSORPTION OF VITAMIN A IN "A"-DEPLETED RATS Duration of study--28 days "A" stores Gain* in rLiver and Kidney-. Vitamin A No. of body wt., /•g./g. Serum Media /•g./Day Animals g. tag./Total Tissue "A," tag. % Oral Corn oil 1 3 60 12.0 1.1 15 Cottonseed oil 1 3 54 6.8 0.8 21 'Topical Corn oil 100 2 25 42.0 8.0 37 Cottonseed oil 100 2 - 1 10.0 1.5 22 * Gain in body weight from time of depletion of vitamin A.

370 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The results obtained with different media are given in Tables 1-4. It is interesting to note that the nature of the medium had a marked influence on the transportation of the vitamin. Figure 1.•Normal control animal. Littebmate control, 56 days old, normal diet• normal skin appearance (X90). Figure 2.•"A"-depleted animal. Rat 56 days old. Signs of vitamin A deficiency are maxi- mal (severe xerophthal•ia and b•y weight loss). This is a relatively normal skin (•90).