Ayman A. Gouda, Ragaa El-Sheikh, Khalil M. Khalil

ABSTRACT

A direct colorimetric method was described for the rapid, sensitive and accurate determination of certain macrolide antibiotics; roxithromycin (ROX), azithromycin (AZM), and clarithromycin (CLM) in bulk powder and in pharmaceutical preparations. The proposed method is based on reaction of the studied drugs with haematoxylin reagent in the presence of boric acid to give a reddish-violet chromogen ?max= 598 nm. The percentage recoveries for the proposed method were 100.42±1.252, 99.59±1.134, and 99.93±1.511 within the concentration range of 0.4–8.0 ?g mL-1, 0.3–6.0 ?g mL-1and 0.2–4.0 ?g mL-1 for ROX, AZM, and CLM, respectively. No interference was observed from the commonly present additives or excipients in pharmaceutical preparations. The proposed method was applied successfully for the determination of the investigated drugs in bulk powder and pharmaceutical dosage forms. The results of the analysis were found to agree statistically with those obtained with the reported methods. Furthermore, the proposed method were validated and also assessed by applying the standard addition technique. Key words: spectrophotometry, macrolide antibiotics, haematoxylin, pharmaceutical preparations.