Thermodynamic study of inclusion complexes of zaleplon with natural and modified cyclodextrins

Mario Jug, Jasna Jablan, Katalin Köver, Tin Weitner, Mario Gabričević

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The thermodynamics and stoichiometry of zaleplon (ZAL) complexation with different cyclodextrin derivatives [β-CD, hydroxypropyl-β-cyclodextrin (HP-β-CD), randomly methylated-β-cyclodextrin (RAMEB), sulphobutylether-β-cyclodextrin (SBE-β-CD)] in aqueous solution was studied by spectrofluorimetry and 1H NMR spectroscopy in order to obtain a more general understanding of the driving forces behind the inclusion phenomena. Job's plot derived from the NMR spectral data and statistical analysis of spectrofluorimetric titration data confirmed the formation of equimolar complexes in all systems tested, excluding the possibility of higher order complex formation. Furthermore, thermodynamic parameters obtained by both techniques gave similar and negative values of ΔG° for all complexes, indicating spontaneous inclusion of drug into CDs. From a thermodynamic point of view, two types of inclusions were determined. One is enthalpy driven ZAL complexation with β-CD, HP-β-CD and RAMEB, while the other is entropy driven complexation observed in the case of SBE-β-CD. The mechanisms behind each type of inclusion were discussed in detail.

Original languageEnglish
Pages (from-to)391-400
Number of pages10
JournalJournal of Inclusion Phenomena and Macrocyclic Chemistry
Volume79
Issue number3-4
DOIs
Publication statusPublished - Aug 2014

Keywords

  • Cyclodextrins
  • Fluorescence
  • Thermodynamics of complexation
  • Zaleplon

ASJC Scopus subject areas

  • Food Science
  • Chemistry(all)
  • Condensed Matter Physics

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