Adapalene-d₃is intended for use as an internal standard for the quantification of adapalene by GC- or LC-MS. Adapalene is a synthetic retinoid and an agonist of retinoic acid receptors (RARs; K_ds = 1,100, 34, and 130 nM for RARα, RARβ, and RARγ, respectively).^1,2,3,4,5It inhibits growth and differentiation of sebocytes in a concentration-dependent manner in primary rat preputial cell culture. Adapalene (10 μM) 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).²It 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.³It inhibits inflammation in rodent models of ear edema induced by arachidonic acid and carrageenan-induced paw edema.²Adapalene (100 μM) 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.^5,4Formulations containing adapalene have been used in the treatment of acne vulgaris.

1.Kim, M.J., Ciletti, N., Michel, S., et al.The role of specific retinoid receptors in sebocyte growth and differentiation in cultureJournal of Investigative Dermatology114349-353(2000) 2.Hensby, C., Cavey, D., Bouclier, M., et al.The in vivo and in vitro anti-inflammatory activity of CD271: A new retinoid-like modulator of cell differentiationAgents Actions29(1-2)56-58(1990) 3.Tenaud, I., Khammari, A., and Dreno, B.In vitro modulation of TLR-2, CD1d and IL-10 by adapalene on normal human skin and acne inflammatory lesionsExp. Dermatol.16(6)500-506(2007) 4.Ocker, M., Herold, C., Ganslmayer, M., et al.The synthetic retinoid adapalene inhibits proliferation and induces apoptosis in colorectal cancer cells in vitroInt. J. Cancer107(3)453-459(2003) 5.Shi, X.-N., Li, H., Yao, H., et al.Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinomaMol. Med. Rep.12(5)6501-6508(2015)