Spectrophotometric and HPLC Determination of Linezolid in Presence of Its Alkaline-Induced Degradation Products and in Pharmaceutical Tablets

Abstract

In this work three sensitive stability-indicating methods for the determination of linezolid in the presence of its alkaline-induced degradation products are developed. The first method depends on the oxidative coupling reaction of linezolid with 3-methyl benzothiazoline-2-one hydrazone (MBTH) hydrochloride in the presence of ferric chloride in an acid medium. The resulting stable colored products showed absorption λmax at 627 nm. The second method is based on alkaline hydrolysis of linezolid to yield the degradation product which reacts with haematoxylin reagent in the presence of boric acid to give a reddish violet chromogen at λmax 557 nm. The third method is based on (HPLC) resolution efficiency in the determination of linezolid in the presence of its alkaline induced degradation product. The percentage recoveries for the proposed methods were 99.54 ± 0.58, 99.84 ± 0.78, and 100.02 ± 0.49 within the concentration range of 1.6–12 µg mL−1, 10–60 ng mL−1 and 5–40 µg mL−1, respectively. The proposed methods were applied successfully for the determination of intact drug in bulk powder, laboratory prepared mixtures containing different percentages of degradation product and pharmaceutical dosage forms. The results of the analysis were found to agree statistically with those obtained with the reported method. Furthermore, the methods were validated and also assessed by applying the standard addition technique.