Química Medicinal

The Use of Chloranilic Acid for the Spectrophotometric Determination of Three Macrolides through Charge Transfer Complex

Abstract

Najma Sultana, Saeed Arayne M and Saeeda Nadir Ali

In the present study, simple and fast spectrophotometricmethod have been reported for the determination of three macrolides i.e., erythromycin, roxithromycin and clarithromycin through charge transfer complexes. The method involves the interaction of macrolides with chloranilic acid in acetonitrile medium. Stoichiometry was found to be 1:1 for all the complexes. Under the optimizedconditions, the complexes were found to be absorbed at 498, 496 and 491 nm with in the linearity range of 3-36, 4-40 and 8-40 μg mL -1 with minimum detection limit 190, 600 and 370 ng mL -1 for respectively. The corresponding molar absorptivity values were determined to be 2.07×10 4 , 1.81×10 4 and 1.67×10 4 Mol -1 cm -1 respectively. The data is discussed in terms of oscillator’s strength, dipole moment, ionization potential, energy of complexes, resonance energy, association constant and Gibb’s free energy changes. Benesi- Hildebrand plots for all complexes have been constructed. Furthermore, the methods were successfully applied for the determination of studied macrolides in pharmaceutical formulations. The interday and intraday precision and percent recovery values were evaluated. Results of analysis were validated successfully. Commonly present excipients did not show interference during analysis