PERCUTANEOUS ABSORPTION OF COSMETIC OILS 275 / •.t -. ,- • ' ., .o}.:..?. .":' ' - -•...:• ..... .., .•.. .•- - :. .•., .,.-....• •..• ..• .... • • .. -t •' .... 4? ,(-•. . '• c•'•'•..?- . 7' •, .... :.:4 './•,• " - ' '...• • • . •" •, ._• ' -'•", •.• •r• - •"•' • •-- . ,.. ,•:•'.:.• • ' •.' • • -• • '•.. ß • . . - ,. -.. - .-, •:• ' . •. .- :.•..., •'. :...•. - • ,. •- "•.: .•-• -- -: . - "' ' •'. ....... ' ' ' '• "• • •-.•"-Qq--s,?•C' •e •" S T':• -• ..--• • • . -.. . '., ß . . •. . - .: • . •'. • .•. -.* ..•-•- •0 ' • . : .. •-•'•,.t • -',• - •: •' , . • .• . •, •' - • , .. •: . ?,%' • . . *-. •.,•,.•.-- -, = . . •. •.•/• '. •- ' ,"• .•.•:' • ... 511 .' •,•.,'•. •,.•. •' *- 'r.•',. *',-,. • . :., • - • ß . *-. *X • . V ' *.-'.•',... ? : * " .... * ' ',) :, , *•**-" .... : V' :X .... '" . Figure 7. Microautoradiograms showing the distribution of radioactivity within the skin of Angora rabbits at various times after 24 hr topical application of •4C-IPM. A) zero day, B) one day, C) $ree days, D) six days, E) ten days. Note the changes of concentration in the sebaceous glands and epidermis tendency continued from one to three days after the finish of application. After six days, however, the grains remained only slightly in the sebaceous glands and became decreased in the dermis. After ten days, the density of grains in the sebaceous glands and the dermis was extremely diminished and almost unseen (Figure 9). 2. Histology: from zero to one day after 24 hr application, edematous changes were mainly observed in the dermis, while acanthosis became increased gradually but quite weakly in the epidermis. From three to six days, acanthosis and edema were found decreased they almost disappeared at ten days. Vasodilatation first appeared at three

276 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 8. Light micrographs showing the histologic•l feature within the skin of Angora r•bbirs •t v•rious rimes after 26 hr topical application of •C-IPM. A) intact skin, B) zero day, C) one day, D) three days, E) six da•s, F) ten da•s. The chan•es of acanthosis in the e•idermis and edema, vasodilamtion and hemorrhage in the dermis were observed days and continued until ten days. The sebaceous glands were found swollen and large through the period of the experiment (Figure 10). METABOLIC FATE AFTER INTRADEKMAL ADMINISTRATION The metabolites were extracted from the skin specimens in which •4C-labelled IPM or HDO was injected. One tenth of the extracts for each specimen was taken for the liquid scintillation counting. Figure 11 shows the recovery percentage of labelled oils