Cyclodextrins: influence of methylation and temperature on kinetics of inclusion complex formation: Investigated by stopped-flow and 1H-NMR line-shape analysis

Fahima Yasen, Michelle Hundevad Rasmussen, Prince Ravichandran, Martin Fromberg & Yasin Yaliniz

Studenteropgave: Bachelorprojekt

Abstrakt

Cyclodextrins (CDs) are cone-shaped molecules with the ability to accommodate hydrophobic molecules known as guest molecules (G), such as pharmaceutical drugs. While structural data and thermodynamic properties are well researched, information on kinetics of complex formation between CD and G is lacking in comparison. Temperature and functional group modifications have been suggested to influence kinetics of CD and G complexation. To investigate these aspects, stopped- flow and 1H-NMR line-shape analysis are applied as real-time and equilibrium kinetic methods. In addition, Isothermal Titration Calorimetry is applied to determine binding constants and fluorescence spectroscopy are used in support of the kinetic methods. In this study, β-CDs with varying degrees of methylation, and the resulting kinetic rate constants of inclusion complex formation with the bile salt glycocholate, have been determined for temperatures 15°C, 25°C and 35°C. Real-time kinetic information could not be obtained, as the stopped-flow analysis procedures were unsuccessful. The obtained equilibrium kinetics indicate that partial methylation of β-CD results in a faster reaction rates, although methylation at the O3 position has a detrimental effect on the reaction rates. A trend was not established between kinetics and temperature, due to inconsistent data. To further investigate the effect of methylation and temperature, it is suggested to perform experiments with a wider range of methylated β-CDs.

UddannelserBasis - Naturvidenskabelig Bacheloruddannelse, (Bachelor uddannelse) Bachelor
SprogEngelsk
Udgivelsesdato25 maj 2018
Antal sider86
VejledereJens Christian Sidney Schönbeck

Emneord

  • Cyclodextrins
  • Kinetics
  • H-NMR
  • Stopped-flow
  • Line-shape
  • ITC
  • Methylation