Original Articles
Jalal H. Abdullah, Tawfeek Ahm
Abstract
The present study describes four simple, rapid, accurate, selective and sensitive spectrophotometric methods for the assay of azithromycin (AZM), a macrolide antibiotic, in bulk drug and pharmaceutical formulation. The methods are based on the formation of yellow ion-pair complex between the AZM and four sulphonphthalein dyes, namely, bromocresol green (BCG), bromocresol purple (BCB), bromophenol blue (BPB), bromothymol blue (BTB) in acetate-acetic acid buffer solution of PH 3.0 or 3.5. The ion-pair complex formed was extracted with chloroform and the absorbance was measured at 418, 409, 415 and 414 nm for BCG, BCB, BPB and BTB methods, respectively. Under the optimized conditions, beer's law is obeyed over the concentration ranges of 2-20, 2-18, 2-12 and 2-14 μgmL-1 for BCG, BCB, BPB and BTB methods, respectively. The molar absorptivity, sandell sensitivity, detection and quantification limits are also calculated. The methods were validated for intra-day and inter-day accuracy and precision, selectivity and robustness and ruggedness. The proposed methods were applied successfully to the determination of AZM in their pharmaceutical formulations and the results were in good agreement with those obtained by the official method. The accuracy and reliability of the proposed methods were further ascertained by recovery studies via standard addition technique.