Procopiou P.A.,Gunnels Wood Road |
Browning C.,Respiratory Biology |
Buckley J.M.,Gunnels Wood Road |
Clark K.L.,Respiratory Biology |
And 14 more authors.
Journal of Medicinal Chemistry | Year: 2011
A series of potent phthalazinone-based human H1 and H 3 bivalent histamine receptor antagonists, suitable for intranasal administration for the potential treatment of allergic rhinitis, were identified. Blockade of H3 receptors is thought to improve efficacy on nasal congestion, a symptom of allergic rhinitis that is currently not treated by current antihistamines. Two analogues (56a and 56b) had slightly lower H1 potency (pA2 9.1 and 8.9, respectively, vs 9.7 for the clinical gold-standard azelastine, and H3 potency (pK i 9.6 and 9.5, respectively, vs 6.8 for azelastine). Compound 56a had longer duration of action than azelastine, low brain penetration, and low oral bioavailability, which coupled with the predicted low clinical dose, should limit the potential of engaging CNS-related side-effects associated with H 1 or H3 antagonism. © 2011 American Chemical Society.