Physicochemical characterization of artemether solid dispersions with hydrophilic carriers by freeze dried and melt methods

Arch Pharm Res. 2010 Jun;33(6):901-10. doi: 10.1007/s12272-010-0613-7. Epub 2010 Jul 6.

Abstract

Solid dispersions of artemether (ARM), a poorly soluble drug, were prepared using polyvinylpyrrolidone (PVPK25, MW 25000) and polyethyleneglycol (PEG4000, MW 4000) as excipients. These dispersions were studied by physical mixture, freeze-drying, and melting methods. They were characterized by X-ray diffraction pattern, fourier transform infrared spectrophotometry, differential scanning calorimetery, and dissolution studies. X-ray diffraction pattern revealed the complete crystalline nature of artemether, whereas physical mixtures, melt mixtures (MM), and freeze-dried solid dispersions (FDSD) of ARM-PVP and ARM-PEG showed reduced peak intensities with increased PVP/PEG content. PEG showed lower decreases in intensity than PVP preparations. Differential scanning calorimetery also confirmed this finding by showing either a small or absent endotherm. Red shifts in O-H stretching vibrations of ARM were higher in the MM of ARM-PVP than its FDSD as exhibited by fourier transform infrared spectrophotometry. The carbonyl peak of PEG was blue shifted in MM and FDSD, whereas the C=O peak of PVP was red shifted in FDSD and MM, indicating different H-bonding by PEG and PVP with ARM. The rate of dissolution (phosphate buffer at pH 4.5) was improved up to 4-fold in MM and FDSD compared to artemether, and up to 50% compared to physical mixtures. The preparation of solid dispersions influenced the rate of dissolution at various drug-carrier ratios, i.e., the dissolution order of 1:1-1:4 ratio was MM > FDSD; FDSD > MM at 1:6-1:8 ratios of both ARM-PVP and ARM-PEG; and FDSD of ARM-PEG > FDSD of ARM-PVP > MM of ARM-PEG > MM of ARM-PVP at a 1:10 ratio.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimalarials / administration & dosage*
  • Antimalarials / analysis
  • Artemether
  • Artemisinins / administration & dosage*
  • Artemisinins / analysis
  • Calorimetry, Differential Scanning
  • Chemical Phenomena
  • Crystallography, X-Ray
  • Drug Carriers / administration & dosage*
  • Drug Carriers / analysis
  • Drug Compounding / methods
  • Excipients / chemistry
  • Freeze Drying
  • Freezing
  • Hydrophobic and Hydrophilic Interactions
  • Polyethylene Glycols / chemistry
  • Povidone / chemistry
  • Schistosomicides / administration & dosage*
  • Schistosomicides / analysis
  • Solubility
  • Spectroscopy, Fourier Transform Infrared
  • Suspensions
  • Time Factors

Substances

  • Antimalarials
  • Artemisinins
  • Drug Carriers
  • Excipients
  • Schistosomicides
  • Suspensions
  • Polyethylene Glycols
  • Artemether
  • Povidone