Navarixin

Navarixin (SCH 527123) is a potent, allosteric and orally active antagonist of both CXCR1 and CXCR2, with K_d values of 41 nM for cynomolgus CXCR1 and 0.20 nM, 0.20 nM, 0.08 nM for mouse, rat and cynomolgus monkey CXCR2, respectivelly^[1][2]. IC50 & Target: Kd: 41 nM (cynomolgus CXCR1), 0.20 nM (mouse CXCR2), 0.20 nM (rat CXCR2), 0.08 nM (cynomolgus monkey CXCR2)^[1] In Vitro: Navarixin is a potent, allosteric antagonist of both CXCR1 and CXCR2, with K_d values of 41 nM for cynomolgus CXCR1 and 0.20 nM, 0.20 nM, 0.08 nM for mouse, rat and cynomolgus monkey CXCR2, respectivelly^[1]. Navarixin (1 nM) reduces CXCL8 potency in stimulating Ba/F3-hCXCR2 chemotaxis. Navarixin (3 nM) significantly inhibits the potency and efficacy of CXCL1-induced neutrophils (PMN) chemotaxis. Navarixin (300 nM) significantly decreases chemokine potency and slightly decreases maximal cell movement for Ba/F3-CXCR1 cells^[2]. Navarixin (25 μM) is sufficient to block IL-8-mediated CXCR2 activation in HCT116, E2, Caco2, and IIIe cells, in which phosphorylation of downstream kinases of CXCR2 is reduced in a concentration-dependent manner^[3]. In Vivo: Navarixin (0.1-10 mg/kg, p.o.) blocks pulmonary neutrophilia (ED₅₀=1.2 mg/kg) and goblet cell hyperplasia (32-38% inhibition at 1-3 mg/kg) in mice following the intranasal lipopolysaccharide (LPS) administration. In rats, Navarixin (0.1-3 mg/kg p.o.) suppresses the pulmonary neutrophilia (ED=1.8 mg/kg) and increase in bronchoalveolar lavage (BAL) mucin content (ED₅₀=0.1 mg/kg) induced by intratracheal (i.t.) LPS^[1].