Abstract | We report on steady-state UV–visible absorption and emission characteristics of Paracetamol, drug used
as antipyretic agent, in water and within cyclodextrins (CDs): ?-CD, 2-hydroxypropyl-?-CD (HP-?-CD)
and 2,6-dimethyl-?-CD (Me-?-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-?-CD shows
the largest effect for the drug. The observed binding constant showing the following trend: Me-?-
CD > HP-?-CD > ?-CD. The less complexing effectiveness of HP-?-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. |