146 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Zusammenfassung In der vorliegenden Arbeit werden in vitro-Screening-Modelle zur Prfifung potentieller Hautfeuchtigkeitsregulatoren vorgestellt weiter wird fiber die FMIR-Analyse als M•3glichkeit zur vergleichenden in vivo- Messung des Hydratationszustandes des Stratum comeurn nach Appli- kation kosmetischer Emulsionen berichtet. Hydagen F, ein Partial-Natriumsalz einer Polyhydroxycarbons•iure, zeigte in diesen Tests ein besonders positives Verhalten. Die Vertraglich- keit dieses neuen kosmetischen Wirkstoffs wurde durch umfangreiche toxikologische Untersuchungen abgesichert. Literaturhinweise {1} Puttnam, N.A., J. Soc. Cosmetic Chemists 23 [41, 209-226 (1972). [21 Dow Chemical Corp., Steinhauer, A.F., DOS 2.-32.161 vom 4.7.1974. 13} DT-AS 2404046, bekanntgemacht am 21.4.1977 [Henkell. 141 Blank, J.H., J. Invest. Dermatol. 18, 433-440 (19521.

J. Soc. Cosmet. Chem., 29, 147-154 (March 1978) Further experience with a topical cream for depigmenting human skin OTTO H. MILLS, JR. and ALBERT M. KLIGMAN Duhring Laboratories, Department of Dermatology, University of Pennsylvania School of Medicine, 3500 Market Street, Suite 203, Philadelphia, PA 19104. Received March 31, 1977. Presented at Annual Meeting, Society of Cosmetic Chemists, December 1974, New York, New York. Synopsis Satisfactory LIGHTENING of HYPERPIGMENTARY SKIN disorders was obtained by twice-daily APPLICATION for two to three months of a PREPARATION containing 5.0% hydroquinone, 0.1% Vi- tamin A acid (tretinoin) and 0.1% dexamethasone, a flourinated corticosteroid. Excellent results were secured in melasma (chloasma) of white females. Two common pigmentary distur- bances in blacks also responded well, namely, the residual hyperpigmentation left by inflammatory acne le- sions and in bearded areas affected by ingrown hairs (pseudofolliculitis). Although senile lentigines were not moderated in patients over 65 years of age, good results were observed in patients 40 to 60 years old. The depigmentation is completely reversible and is not attended by significant local or systemic side effects. INTRODUCTION In a previous work, we showed that a formulation containing Vitamin A acid (tretinoin), hydroquinone and a corticosteroid could bring about complete loss of melanin from the skin of normal blacks and was highly beneficial in disorders of hy- perpigmentation, notably melasma (chloasma), freckles and excess pigmentation following inflammation (1). Bleaching occurred despite an increase in the density of pigment-forming cells (mel- anocytes). Each of the three components was essential for effectiveness. Hydro- quinone is known to interfere with the tyrosine-tyrosinase pathway of melanin syn- thesis. This drug also causes subcellular membrane damage and inhibits the formation of melanosomes, the organelles in which melanin is packaged (2). By itself, its effec- tiveness is too limited. How tretinoin and corticosteroids contribute to the depigment- ing action is conjectural. The latter may inhibit melanin production by melanocytes in the same way that it suppresses collagen synthesis by fibroblasts, presumably through a repression of the general metabolic activity of the cell steriods are known to be cyto- static to the epidermis (3). Tretinoin, on the other hand, stimulates cell turnover (4) 147