文摘
We report on steady-state UV–visible absorption and emission characteristics of Paracetamol, drug used as antipyretic agent, in water and within cyclodextrins (CDs): x3b2;-CD, 2-hydroxypropyl-x3b2;-CD (HP-x3b2;-CD) and 2,6-dimethyl-x3b2;-CD (Me-x3b2;-CD). The results reveal that Paracetamol forms a 1:1 inclusion complex with CD. Upon encapsulation, the emission intensity enhances, indicating a confinement effect of the nanocages on the photophysical behavior of the drug. Due to its methyl groups, the Me-x3b2;-CD shows the largest effect for the drug. The observed binding constant showing the following trend: Me-x3b2;-CD > HP-x3b2;-CD > x3b2;-CD. The less complexing effectiveness of HP-x3b2;-CD is due to the steric effect of the hydroxypropyl-substituents, which can hamper the inclusion of the guest molecules. The solid state inclusion complex was prepared by co-precipitation method and its characterization was investigated by Fourier transform infrared spectroscopy, 1H NMR and X-ray diffractometry. These approaches indicated that Paracetamol was able to form an inclusion complex with CDs, and the inclusion compounds exhibited different spectroscopic features and properties from Paracetamol.