Effect of β-sitosterol concentration and high pressure homogenization on the chlorhexidine release from vesicular gels

E. Farkas, R. Schubert, R. Zelkó

Research output: Contribution to journalArticle

4 Citations (Scopus)


Previous studies have confirmed that the phase transition of vesicular gels of hydrogenated phospholipids to the less ordered fluid vesicular state was induced by the increase of the β-sitosterol ratio in the whole gel system and consequently in the lipid bilayer. The purpose of the present study was to evaluate the influence of the β-sitosterol portion in the lipid bilayer and the effect of high pressure homogenization on the structural characteristics of the prepared gel systems. In addition the influence of β-sitosterol on the consequent chlorhexidine release from the obtained vesicles and liposomes was also examined. Lipid mixtures were prepared from different molar ratios of lecithin:sterol components (90:10-65:35 mol%). The obtained mixtures were hydrated with the aqueous solution of chlorhexidine digluconate in order to achieve a 30% (w/w) final concentration of the lipid mixtures and a 4% (w/w) concentration of the drug. One portion of the resultant multilamellar vesicles was homogenized by using high pressure. To characterize the homogenized and non-homogenized systems, transmission electron microscopy of the freeze-fractured samples and differential scanning calorimetry (DSC) were carried out. A vertical type diffusion cell was applied to determine the amount of released chlorhexidine digluconate. Along with the increase in β-sitosterol concentration, the fluidity of the membrane as well as its permeability also increased. The increased permeability - caused by the higher β-sitosterol concentration - and the high pressure homogenization, which increased the dispersity and therefore the surface area, enabled a higher amount of chlorhexidine to be released. The increase of drug release was more pronounced in the case of samples prepared with high pressure homogenization.

Original languageEnglish
Pages (from-to)51-55
Number of pages5
JournalInternational Journal of Pharmaceutics
Issue number1
Publication statusPublished - Jan 3 2006


  • Chlorhexidine digluconate release
  • Differential scanning calorimetry
  • High pressure homogenization
  • Multilamellar vesicles (MLV)
  • Transmission electron microscopy
  • Vesicular phospholipid gel (VPG)
  • β-sitosterol

ASJC Scopus subject areas

  • Pharmaceutical Science

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