Tofacitinib (CP690550) Citrate

Description: Tofacitinib citrate (formerly CP-690550 citrate), the citrate salt of tofacitinib (tasocitinib or CP 690550, brand Xeljanz), is a novel, potent and orally bioavailable inhibitor of JAK3 (Janus-Associated kinase) with IC50 of 1 nM in cell-free assays. In May 2018, the U.S. FDA approved tofacitinib citrate for the treatment of adult patients with moderately to severely active ulcerative colitis. It is the first oral drug approved for chronic use in ulcerative colitis. The inhibition is JAK3 specific with a selectivity 1000-fold more than other non-JAK family kinases. Besides inhibiting JAK3 (with IC50 of 1 nM), tofacitinib also inhibits JAK2 and JAK1 with 20- and 100-fold less in potency respectively. However, in a recent study, the binding affinities (Ki) of tofacitinib towards JAK1, JAK2, and JAK3 were reported to be 1.6 nM, 21.7 nM, and 6.5 nM respectively.

References: J Med Chem. 2010 Dec 23; 53(24):8468-84; Cancer Sci. 2008 Jun; 99(6):1265-73; J Leukoc Biol. 2004 Dec; 76(6):1248-55.

Related CAS: 477600-75-2 (free base); 1092578-47-6 (3S, 4S)-Tofacitinib; 1092578-48-7 (3S, 4R)-Tofacitinib; 1092578-46-5 (3R, 4S)-Tofacitinib; 1259404-17-5 (Tofacitinib racemate); 540737-29-9 (citrate); 1443435-54-8 (oxalate); 1443435-50-4 (tartrate); 1803005-18-6 (HCl); 1803005-19-7 (HBr); 2052885-67-1 (maleate)