PHARMACOLOGY OF ADAPALENE

Adapalene, a synthetic retinoid, is a new drug proposed for the treatm ent of acne patients. Studies on the in vitro and in vivo pharmacology of adapalene have shown that it is very active on cell and tissue pro liferation and differentiation. Furthermore, adapalene has anti-inflam matory potential as determined by its anti-AP1 activity, Adapalene int eracts selectively with the nuclear receptors RAR beta and RAR gamma, and its activity on proliferation and differentiation can be blocked b y a RAR beta-gamma antagonist, Because RAR beta is not expressed in hu man keratinocytes, the effect of adapalene on the major cell type of t he epidermis is certainly mediated by its interaction with RAR gamma, The unique pharmacological properties of adapalene may explain why, wh en compared to tretinoin, it has an improved therapeutic ratio due to its better tolerance.