Acta Pharm. 66 (2016) 533-542

 

full paper

Original research paper

 

Charge transfer interaction of organic p-acceptors with the anti-hyperuricemic drug allopurinol: Insights from IR, Raman, 1H NMR and 13C NMR spectroscopies

MOAMEN S. REFAT, HOSAM A. SAAD, ABDEL MAJID A. ADAM, MOHAMED A. AL-OMAR and AHMED M. NAGLAH

msrefat@yahoo.com

1 Department of Chemistry, Faculty of Science, Taif University, Al-Haweiah, P.O. Box 888, Zip Code 21974, Taif, Saudi Arabia

2 Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt

3 Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt

4 Department of Pharmaceutical Chemistry, Drug Exploration and Development Chair, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia

5 Peptide Chemistry Department, Chemical Industries Research Division, National Research Centre, 12622-Dokki, Cairo, Egypt

Accepted July 25, 2016

Published online August 2, 2016

 

The topic of charge-transfer (CT) complexation of vital drugs has attracted considerable attention in recent years owing to their significant physical and chemical properties. In this study, CT complexes derived from the reaction of the anti-hyperuricemic drug allopurinol (Allop) with organic p-acceptors [(picric acid (PA), dichlorodicyanobenzoquinone (DDQ) and chloranil (CHL)] were prepared, isolated and characterized by a range of physicochemical methods, such as IR, Raman, 1H NMR and 13C NMR spectroscopy. The stoichiometry of the complexes was verified by elemental analysis. The results show that all complexes that were formed were based on a 1:1 stoichiometric ratio. This study suggests that the complexation of Allop with either the DDQ or CHL acceptor leads to a direct pp* transition, whereas the molecules of Allop and PA are linked by intermolecular hydrogen-bonding interactions.

 

Keywords: allopurinol, p-acceptor, charge-transfer, proton-transfer