Stability and structure of inclusion complexes of zaleplon with natural and modified cyclodextrins

Scientific paper - Original scientific paper

• Author: Mario Jug
• Author: Mario Gabričević
• Author: Tin Weitner
• Author: Jasna Jablan
• Author's institution: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of pharmaceutical technology)
• Author's institution: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of general and inorganic chemistry)
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract (english)

The interaction between zaleplon (ZAL) and different cyclodextrins in aqueous solutions was
investigated by spectrofluorimetric and phase solubility studies. Stability constants determined by both
methods showed that among natural cyclodextrins, β-cyclodextrin (βCD) formed the most stabile complex
but its solubilizing efficiency was limited. Among βCD derivatives, the complex stability and solubilisation
efficiency decreased in order: randomly methylated-βCD (RAMEB) > sulphobutylether-βCD
(SBEβCD ) > hydroxypropyl-βCD (HPβCD). The inclusion complexes of ZAL with βCD and RAMEB
were further characterised by 1H-NMR spectroscopy and the inclusion complex formation was confirmed
in both cases. ROESY spectra showed two binding modes between ZAL and βCD which exist simultaneously
in the solution. The first binding mode occurs by the inclusion of the phenyl ring of ZAL into the
βCD central cavity via the wider rim of the cyclodextrin cone and is dominant. The second one is formed
by the inclusion of pyrazolo[1,5-a]pyrimidine ring of ZAL.(doi: 10.5562/cca1800)

• Keywords (english): Cyclodextrins; Zaleplon; Inclusion Complexes; Stability Constants; Fluorescence; 1H-NMR
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Croatica Chemica Acta
• Numbering: vol. 84, no. 2, pp. 169-178
• p-ISSN: 0011-1643
• e-ISSN: 1334-417X
• DOI: https://doi.org/10.5562/cca1800
• URN:NBN: urn:nbn:hr:163:767001
• Publication: 2011
• Document URL: https://hrcak.srce.hr/71979
• Type of resource: Text
• Access conditions: Open access
• Created on: 2020-04-17 16:36:04