Efficient, large-scale synthesis and preclinical studies of MRS5698, a highly selective A3 adenosine receptor agonist that protects against chronic neuropathic pain

Purinergic Signal. 2015 Sep;11(3):371-87. doi: 10.1007/s11302-015-9459-2. Epub 2015 Jun 27.

Abstract

We reported that 2-(3,4-difluorophenylethynyl)-N (6)-3-chlorobenzyl (N)-methanocarba adenosine derivative 1 (MRS5698) binds selectively to human and mouse A3 adenosine receptors (A3ARs, K i 3 nM). It is becoming an important pharmacological tool for defining A3AR effects and is orally active in a chronic neuropathic pain model. Here, we introduce a new synthetic route for MRS5698 from D-ribose, suitable for a scale-up on a multi-gram scale, and we measure in vitro and in vivo ADME-Tox parameters. MRS5698 was very stable in vitro, failed to inhibit CYPs at <10 μM, and was largely bound to plasma proteins. It was well tolerated in the rat at doses of ≤200 mg/kg i.p. A 1 mg/kg i.p. dose in the mouse displayed t 1/2 of 1.09 h and plasma Cmax of 204 nM at 1 h with an AUC of 213 ng × h/mL. CACO-2 bidirectional transport studies suggested intestinal efflux of MRS5698 (efflux ratio 86). Although the oral %F is only 5 %, the beneficial effect to reverse pain lasted for at least 2 h in the CCI model in rats, using the same vehicle for oral administration of a high dose. The stability, low toxicity, lack of CYP interaction, pharmacokinetic half-life, and in vivo efficacy suggest that MRS5698 is a preferred compound for further consideration as a treatment for neuropathic pain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / pharmacokinetics
  • Adenosine / therapeutic use
  • Adenosine / toxicity
  • Adenosine A3 Receptor Agonists / pharmacokinetics
  • Adenosine A3 Receptor Agonists / therapeutic use*
  • Adenosine A3 Receptor Agonists / toxicity
  • Animals
  • Biological Transport, Active
  • Blood Proteins / metabolism
  • Caco-2 Cells
  • Chronic Disease
  • Constriction, Pathologic / complications
  • Half-Life
  • Humans
  • In Vitro Techniques
  • Male
  • Microsomes, Liver
  • Mutagenicity Tests
  • Neuralgia / drug therapy*
  • Protein Binding
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Adenosine A3 Receptor Agonists
  • Blood Proteins
  • MRS5698
  • Adenosine