Adapalene is a synthetic retinoid and an agonist of retinoic acid receptors (RARs; Kds = 1,100, 34, and 130 nM for RAR+, RAR, and RAR, respectively).1,2,3,4,5 It inhibits growth and differentiation of sebocytes in a concentration-dependent manner in primary rat preputial cell culture. Adapalene (10 M) completely inhibits the activity of soybean 15-lipoxygenase (15-LOX) in an enzyme assay and inhibits the 5- and 15-LOX pathways in human blood polymorphonuclear leukocytes (PMNs).2 It reduces the protein levels of toll-like receptor 2 (TLR2) and IL-10 in skin explants isolated from patients with acne and healthy controls in a concentration-dependent manner but increases the expression of the antigen-presenting protein CD1d in acne skin explants while decreasing it in control explants.3 It inhibits inflammation in rodent models of ear edema induced by arachidonic acid and carrageenan-induced paw edema.2 Adapalene (100 M) also induces apoptosis and inhibits proliferation of CC-531, HT-29, and LoVo colon cancer cells and reduces tumor growth in a DLD-1 colon cancer nude mouse xenograft model in a dose-dependent manner.5,4 Formulations containing adapalene have been used in the treatment of acne vulgaris.
A crystalline solid
SHIPPING & STORAGE
Room temperature in continental US; may vary elsewhere