Physicochemical and pharmacokinetic characterization of amorphous solid dispersion of tranilast with enhanced solubility in gastric fluid and improved oral bioavailability

Drug Metab Pharmacokinet. 2012;27(4):379-87. doi: 10.2133/dmpk.dmpk-11-rg-101. Epub 2012 Jan 13.

Abstract

In the present study, amorphous solid dispersion (ASD) formulations of tranilast (TL) with 8 hydrophilic polymers were prepared by a solvent evaporation method with the aim of improving dissolution behavior in gastric fluid and thereby enhancing oral bioavailability. The physicochemical properties were characterized with a focus on morphology, crystallinity, thermal behavior, dissolution, drug-polymer interaction, and stability. Of all TL formulations, ASD formulation with Eudragit EPO exhibited the highest improvement in dissolution behavior with a 3,000-fold increase in the first-order dissolution rate under acidic conditions (pH 1.2). Spectroscopic studies using infrared and near-infrared analyses revealed the drug-polymer interaction in the Eudragit EPO-based ASD formulation. On the basis of dissolution, crystallinity, and stability data, the maximum allowable drug load in the Eudragit EPO-based ASD formulation was deduced to be ca. 50%. Pharmacokinetic profiling of orally dosed TL formulations in rats was also carried out using UPLC/ESI-MS. After oral administration of the Eudragit EPO-based ASD formulation in rats, enhanced TL exposure was observed with an increase of oral bioavailability by 19-fold, and the variation of AUC was ca. 4 times lower than that with crystalline TL. With these data, the ASD approach could be a viable formulation strategy for enhancing the wettability and oral bioavailability of TL, resulting in improved therapeutic potential of TL for the treatment of inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / administration & dosage*
  • Anti-Inflammatory Agents, Non-Steroidal / blood
  • Anti-Inflammatory Agents, Non-Steroidal / chemistry
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacokinetics*
  • Area Under Curve
  • Biological Availability
  • Calorimetry, Differential Scanning
  • Chemistry, Pharmaceutical
  • Chromatography, Liquid
  • Crystallization
  • Crystallography, X-Ray
  • Drug Stability
  • Gastric Juice / chemistry
  • Hydrogen-Ion Concentration
  • Hydrophobic and Hydrophilic Interactions
  • Injections, Intravenous
  • Male
  • Metabolic Clearance Rate
  • Microscopy, Electron, Scanning
  • Microscopy, Polarization
  • Models, Biological
  • Polymethacrylic Acids / chemistry
  • Powder Diffraction
  • Rats
  • Rats, Sprague-Dawley
  • Solubility
  • Spectrometry, Mass, Electrospray Ionization
  • Spectroscopy, Fourier Transform Infrared
  • Spectroscopy, Near-Infrared
  • Technology, Pharmaceutical / methods
  • ortho-Aminobenzoates / administration & dosage*
  • ortho-Aminobenzoates / blood
  • ortho-Aminobenzoates / chemistry
  • ortho-Aminobenzoates / pharmacokinetics*

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Polymethacrylic Acids
  • ortho-Aminobenzoates
  • Eudragit E PO
  • tranilast