PSB-603 is a potent and highly selective A2B adenosine receptor antagonist exhibiting a Ki value of 0.553 nM and virtually no affinity for the human and rat A1 and A2A and the human A3 receptors up to a concentration of 10 μM.In Vitro: PSB-603 is a potent and selective adenosine A2B receptor antagonist exhibiting a Ki value of 0.553 nM at the human A2B receptor and virtually no affinity for the human and rat A1 and A2A and the human A3 receptors up to a concentration of 10 μM.In Vivo: PSB-603 shows anti-inflammatory effect in local and systemic inflammation models. PSB-603 (5 mg/kg b.w. ip) significantly reduces inflammation in two mice models of inflammation (local and systemic). PSB-603 significantly decreases levels of the inflammatory cytokines IL-6, TNF-α and of ROS in the inflamed paw and reduces inflammation of the peritoneum by significantly decreasing the infiltration of leukocytes. PSB-603 is administered as suspensions in 1 % Tween 80.