: LABS Consortium, Antimicrobial Activity, Adhesion, Auto aggregation, Co Aggregation

A novel 96-microwell-based visible spectrophotometric assay was developed and validated for the determination of Azithromycin in tablets and capsules. The formation of a coloured charge-transfer complex between Azithromycin as n-electron donor, and 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone, as π-electron acceptor, was investigated and employed as a basis for the development of the proposed assay in a 96 micro well Thermomax plate reader. A UV-Visible spectrophotometer was used for the study of the complex behaviour at 518 nm, while Thermomax 96-microwell plate reader was used for the content determination of Azithromycin tablet and capsule brands at 450 nm. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient was found between the absorbance and the concentration of Azithromycin in the range of 0.026 ? 0.105 mg/ml, with the equation y=0.048x and R2= 0.984. The Gibbs free energy, ?G, was found to be negative at different temperatures. The limits of detection and quantisation were found to be 0.023 and 0.069 mg/ml respectively. The procedure gave good precision. The assay was applied successfully to the analysis of azithromycin in tablets and capsules with satisfactory result. The assay described has high throughput property, consumes little volume of organic solvent, offers reduction in analysis cost and the exposure of the analyst to the toxic effects of organic solvent.