Retinol or retinal has been known to be effective against skin disorders such as wrinkles, warts, eczema, and dandruff (European Published Unexamined Patent Application No. 391033, U.S. Pat. No. 3,932,665, U.S. Pat. No. 4,934,114 and the like). Retinoic acid has been known to reduce wrinkles (European Published Unexamined Patent Application No. 379367, Drugs and Aging, 2, pp. 7-13, 1992). This substance has been used in the United States as a medicament for treatment of skin damaged from ray of sunlight. It is reported that wrinkles caused by aging can be treated with retinal, retinal, and retinoic acid (U.S. Published Unexamined Patent Application No. 2001/53347). However, retinoic acid is highly irritative to skin and induces flare or inflammatory dermatitis. Therefore, development of an anti-wrinkle agent which is low epispastic has been desired.
The term “retinoids” is a general name for compounds which exert similar actions to those of retinoic acid or a part of the actions by binding to receptors that are essential for expression of the physiological actions of all-trans-retinoic acid or 9-cis-retinoic acid (three sub-types of each receptor are known to exist). Among them, some compounds have almost the same level of actions as that of retinoic acid or a higher level of actions. However, a skin irritative action generally increases in proportion to the level of the pharmacological actions (J. Med. Chem., 32, pp. 834-840, 1989). Moreover, 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl) carbamoyl]benzoic acid, one of typical retinoids, has been reported to be ineffective on dermatopathy caused by rays of sunlight (WO96/30009).
USPTO Backgrounds
USPTO Backgrounds