The discovery of quinoline based single-ligand human H 1 and H 3 receptor antagonists.

A novel series of potent quinoline-based human H1 and H3 bivalent histamine receptor antagonists, suitable for intranasal administration for the potential treatment of allergic rhinitis associated nasal congestion, were identified. Compound 18b had slightly lower H1 potency (pA2 8.8 vs 9.7 for the clinical goldstandard azelastine), and H3 potency (pKi 9.1vs 6.8 for azelastine), better selectivity over α1A , α1B and hERG, similar duration of action, making 18b a good back-up compound to our previous candidate, but with a more desirable profile.