Chimie médicale

Spectrophotometric Determination of Quinolones by Charge Transfer Complexation with Chloranilic Acid: Synthesis and Characterization

Abstract

Muhammad Saeed Arayne, Najma Sultana and Saeeda Nadir Ali

A simple and sensitive spectrophotometric method has been described for the assay of quinolones in bulk drug and in pharmaceutical formulations. The developed method is based on the formation of colored charge transfer complexes of quinolones with chloranilic acid in acetonitrile solvent. The formed complexes absorbed at 417, 436, 419 and 436 nm for sparfloxacin, enoxacin, norfloxacin and levofloxacin respectively. Beer’s law is obeyed in the concentration range of 0.5-7, 1-10, 1-10 and 1-5 μg mL -1 with LLOD values 0.036, 0.0041, 0.0344 and 0.0063 ng mL -1 respectively. The data are discussed in terms of molar absorptivity, association constant and Gibb’s free energy. Spectral characteristics including oscillator’s strength, dipole moment, ionizationpotential, energy of complexes and resonance energy have been determined. Benesi-Hildebrand plots for each complex have been constructed. Structural characteristics of synthesized charge transfer complexes were determined by IR spectroscopy. The applicability of the method was demonstrated by determination of studied drugs in commercial tablets with satisfactory results. No interference from excipients was observed in the formulation