Abstract
The present study describes the development and validation of a microwell-based spectrophotometric method for determination of azithromycin (AZM) in its pharmaceutical formulations. In this method, the charge transfer (CT) reaction between AZM as n-electron donor and 2,3-dichloro-5,6-dicyano- 1,4-benzoquinone (DDQ) as a pi-electron acceptor was performed in the 96-microwells. The color signals of the CT complex were measured at 450 nm by microwell-plate absorbance reader. The optimum conditions for the proposed method were established and the analytical procedures were recommended. The proposed method offered high sensitivity and precision; the limits of detection and quantitation were 5.6 and 16.9 mu g/well, respectively. The proposed method was successfully applied to the analysis of pharmaceutical formulations (tablets) that contain AZM with good accuracy and precision, and the results were compared favorably with a reference method. The method described herein has great practical value in the routine analysis of AZM in quality control laboratories, as it has a high throughput property and offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and consequently reduction in the analysis cost. Although the method was validated for AZM, however, the same methodology could be used for electron-donating analyte for which a CT reaction can be performed.