Abstract

STABILITY INDICATING ANALYTICAL METHOD VALIDATION FOR DETERMINATION OF RELATED SUBSTANCES OF ESZOPICLONE IN TABLET DOSAGE FORM

Asheesh Singh* Parul Singh

ABSTRACT

Eszopiclone is a nonbenzodiazepine hypnotic used as a treatment for insomnia. Eszopiclone is the active dextrorotatory stereoisomer of zopiclone and belongs to the class of drugs known as cyclopyrrolones. A simple, sensitive, stability-indicating reversed-phase high-performance liquid chromatographic method was developed for the determination of eszopiclone and related impurities in tablet dosage form. The chromatographic separation was achieved on an Zorbax XDB C18 column(250 3 4.6 mm, 5 mm), using a mobile phase consisting of 0.05M monobasic sodium phosphate buffer containing 0.7% sodium laurylsulfate (pH 3.5) and acetonitrile in the ratio of 60:40 (v/v), at a flow rate of 1.5 mL/min and temperature of 40°C. Quantification was achieved with photodiode array detection at 303 nm. The described method showed excellent linearity over a range of limits of quantification to 4.8 mg/mL (150% of specification limit; i.e., 3.2 mg/mL). The drug product was subjected to the stress conditions of oxidative, acid, base, thermal and photolytic degradation. Eszopiclone degradation was observed in acid hydrolysis, base hydrolysis and peroxide stress conditions. Eszopiclone was stable in thermal and photolytic degradation conditions. The method is validated for the quantification of impurities and degradation products of eszopiclone in tablet dosage form.

Keywords: Eszopiclone (ESZ), Hypnotic agent, Analytical Method, Validation, High performance Liquid Chromatography.