3-alkoxy-pyrrolo[1,2-b]pyrazolines as selective androgen receptor modulators with ideal physicochemical properties for transdermal administration

J Med Chem. 2014 Sep 11;57(17):7396-411. doi: 10.1021/jm5009049. Epub 2014 Aug 26.

Abstract

We describe the synthesis and characterization of 3-alkoxy-pyrrolo[1,2-b]pyrazolines as novel selective androgen receptor (AR) modulators that possess excellent physicochemical properties for transdermal administration. Compound 26 bound to human AR with an IC50 of 0.7 nM with great selectivity over other nuclear hormone receptors and potently activated AR in a C2C12 muscle cell reporter gene assay with an EC50 of 0.5 nM. It showed high aqueous solubility of 1.3 g/L at pH 7.4, and an in silico model as well as a customized parallel artificial membrane permeability assay indicated good skin permeation. Indeed, when measuring skin permeation through excised human skin, an excellent flux of 2 μg/(cm(2)·h) was determined without any permeation enhancers. In a 2 week Hershberger model using castrated rats, the compound showed dose-dependent effects fully restoring skeletal muscle weight at 0.3 mg/kg/day after subcutaneous administration with high selectivity over prostate stimulation.

MeSH terms

  • Administration, Cutaneous
  • Androgen Receptor Antagonists / chemistry*
  • Androgen Receptor Antagonists / metabolism
  • Androgen Receptor Antagonists / pharmacokinetics
  • Androgens / chemistry*
  • Androgens / metabolism
  • Animals
  • Area Under Curve
  • Azabicyclo Compounds / chemistry*
  • Azabicyclo Compounds / metabolism
  • Azabicyclo Compounds / pharmacokinetics
  • Binding Sites
  • Binding, Competitive
  • Cell Line
  • Chemical Phenomena
  • Crystallography, X-Ray
  • Humans
  • Male
  • Metabolic Clearance Rate
  • Mice
  • Models, Chemical
  • Models, Molecular
  • Molecular Structure
  • Protein Structure, Tertiary
  • Pyrazoles / chemistry*
  • Pyrazoles / metabolism
  • Pyrazoles / pharmacokinetics
  • Rats, Wistar
  • Receptors, Androgen / chemistry*
  • Receptors, Androgen / metabolism
  • Skin / metabolism

Substances

  • 2-chloro-4-(4-hydroxy-3-methoxy-3a,4,5,6-tetrahydro-3H-pyrrolo(1,2-b)pyrazol-2-yl)-3-methylbenzonitrile
  • AR protein, human
  • Androgen Receptor Antagonists
  • Androgens
  • Azabicyclo Compounds
  • Pyrazoles
  • Receptors, Androgen