In order to have a preliminary insight into the affinity of ralixofene towards the bradykinin receptors, the compound was first tested at 20 µM for its capacity to displace a reference ligand from B1 and B2, respectively. Specifically, desArg10-kallidin was used in the case of the B1 receptor and NPC 567 for the B2 receptor. The results of this study indicate that at this concentration, ralixofene does not displace desArg10-kallidin at the B1 receptor, whereas the reference ligand at the B2 receptor is displaced ~54%. We subsequently proceeded to carry out a study of the pharmacodynamic profile of the compound towards the BK B2 receptor in vitro, using a functional efficacy measurement [31]. Accordingly, we tested its capacity to antagonize BK on Chinese Hamster Ovary (CHO) cells stably transfected with the B2 receptor.