1. Academic Validation
  2. The discovery of phthalazinone-based human H1 and H3 single-ligand antagonists suitable for intranasal administration for the treatment of allergic rhinitis

The discovery of phthalazinone-based human H1 and H3 single-ligand antagonists suitable for intranasal administration for the treatment of allergic rhinitis

  • J Med Chem. 2011 Apr 14;54(7):2183-95. doi: 10.1021/jm1013874.
Panayiotis A Procopiou 1 Christopher Browning Jennifer M Buckley Kenneth L Clark Lise Fechner Paul M Gore Ashley P Hancock Simon T Hodgson Duncan S Holmes Michael Kranz Brian E Looker Karen M L Morriss Daniel L Parton Linda J Russell Robert J Slack Steven L Sollis Sadie Vile Clarissa J Watts
Affiliations

Affiliation

  • 1 Department of Medicinal Chemistry, GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, United Kingdom. pan.a.procopiou@gsk.com
Abstract

A series of potent phthalazinone-based human H(1) and H(3) bivalent Histamine Receptor antagonists, suitable for intranasal administration for the potential treatment of allergic rhinitis, were identified. Blockade of H(3) 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 H(1) potency (pA(2) 9.1 and 8.9, respectively, vs 9.7 for the clinical gold-standard azelastine, and H(3) 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 H(3) antagonism.

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