Molecular interaction between nonsteroidal anti-inflammatory drug molecules with cucurbit[7]uril estimated by spectroscopy and calorimetry

Abstract

Abstract The supramolecular interaction of nonsteroidal anti-inflammatory drug molecules with macrocyclic hosts is one of the interesting areas of research. In this study the interaction of Indomethacin and Acemetacin with macrocyclic cucurbit[7]uril in aqueous medium is reported. The supramolecular interaction of the drug molecules with macrocyclic host have been studied by using the steady state absorption, fluorescence, time resolved fluorescence emission spectroscopy and isothermal titration calorimetry. The modulation of spectral features of the drug molecules on addition of cucurbit[7]uril indicates that the interaction takes place between the drug molecules with cucurbit[7]uril, respectively. Indomethacin and Acemetacin form 1:1 complex with cucurbit[7]uril. The binding strength and stoichiometry of the drug molecules with cucurbit[7]uril have been estimated by using fluorescence and isothermal titration calorimetry measurements, respectively. The driving forces involved for the complexation of both the drug molecules with cucurbit[7]uril have been obtained from isothermal titration calorimetry measurement. This study will be helpful to get the knowledge about the modulation of photophysical properties of the studied drugs on addition of macrocyclic host cucurbit[7]uril. The changes in thermodynamic properties due to the complexation of the drug molecules with cucurbit[7]uril help to understand about the governing parameters involved in this complexation. This study will be helpful for the use of cucurbit[7]uril as a potential drug delivery system.