(-)-(9S)-9-(3-Bromo-4-fluorophenyl)-2,3,5,6,7,9-hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide (A-278637), a novel ATP-sensitive potassium channel opener: hemodynamic comparison to ZD-6169, WAY-133537, and nifedipine in the anesthetized canine

J Cardiovasc Pharmacol. 2004 Aug;44(2):137-47. doi: 10.1097/00005344-200408000-00001.

Abstract

The therapeutic utility of KATP channel opening agents (KCOs) in the treatment of overactive bladder may be limited by hypotension as a result of insufficient selectivity in vivo for bladder versus vasculature smooth muscle. Recently, we demonstrated that the putative uroselective KCOs, A-278637, ZD-6169, and WAY-133537 suppress unstable bladder contraction in an in vivo pre-clinical pig model of detrusor instability secondary to partial outlet obstruction. In the present study in the anesthetized dog we targeted plasma concentrations 3-, 10-, and 30-fold above a common index of in vivo efficacy (EC35) for suppression of unstable bladder contraction in pigs, to provide a comprehensive cardiovascular profile of these compounds. When compared at similar multiples of efficacy, dose-dependent reductions in SVR were greater in ZD-6169 and WAY-133537-treated animals versus A-278637. A-278637, unlike ZD-6169 or WAY-133537, produced no effect on MAP at concentrations 10-fold above the EC35. At concentrations 30-fold above the EC35, MAP in A-278637-treated animals was reduced -11% from baseline versus -24% and -42% for ZD-6169 and WAY-133537. Accordingly, at plasma concentrations approximately 30-fold above the EC35 reflex-mediated increases in HR were modest for A-278637-treated animals (15% above baseline) versus ZD-6169 (22%) or WAY-133537 (35%). Increases in both dP/dt and cardiac output occurred at lower therapeutic multiples and were greater in magnitude for animals treated with WAY-133537 (66% and 64% above baseline, respectively, 60 minutes into compound infusion) and ZD-6169 (10% and 13%) versus A-278637 (-2% and 6%). Thus, A-278637 exerted lesser effects on cardiovascular function at equivalent multiples of the EC35 than either ZD-6169 or WAY-133537. These data suggest that A-278637 possesses a greater functional selectivity for urinary bladder versus vascular smooth muscle in vivo and that A-278637 may exhibit a more favorable therapeutic index than either ZD-6169 or WAY-133537.

Publication types

  • Comparative Study

MeSH terms

  • Adenosine Triphosphate / chemistry
  • Amides / blood
  • Amides / pharmacology*
  • Animals
  • Benzophenones / blood
  • Benzophenones / pharmacology*
  • Blood Pressure / drug effects
  • Cyclic S-Oxides / blood
  • Cyclic S-Oxides / pharmacology*
  • Cyclobutanes / blood
  • Cyclobutanes / pharmacology*
  • Disease Models, Animal
  • Dogs
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical
  • Electrocardiography / methods
  • Heart Rate / drug effects
  • Hypotension / chemically induced
  • Infusions, Intravenous
  • Ion Channel Gating / drug effects
  • Ion Channel Gating / physiology
  • Male
  • Muscle Contraction / drug effects
  • Muscle, Smooth / drug effects
  • Nifedipine / blood
  • Nifedipine / pharmacology*
  • Nitriles / blood
  • Nitriles / pharmacology*
  • Pharmaceutical Vehicles / administration & dosage
  • Pharmaceutical Vehicles / chemistry
  • Polyethylene Glycols / administration & dosage
  • Polyethylene Glycols / chemistry
  • Potassium Channels / drug effects
  • Potassium Channels / physiology*
  • Quinolones / blood
  • Quinolones / pharmacology*
  • Tachycardia / chemically induced
  • Urinary Bladder / drug effects
  • Urinary Bladder / physiology
  • Urinary Incontinence / drug therapy
  • Urinary Incontinence / physiopathology
  • Vascular Resistance / drug effects

Substances

  • 9-(3-bromo-4-fluorophenyl)-2,3,5,6,7,9-hexahydrothieno(3,2-b)quinolin-8(4H)-one 1,1-dioxide
  • Amides
  • Benzophenones
  • Cyclic S-Oxides
  • Cyclobutanes
  • Nitriles
  • Pharmaceutical Vehicles
  • Potassium Channels
  • Quinolones
  • WAY 133537
  • Zeneca ZD 6169
  • Polyethylene Glycols
  • Adenosine Triphosphate
  • Nifedipine