Validated RP-HPLC Method for the Estimation of Eszopiclone in Bulk and Tablet Dosage Form

A simple, selective, linear, precise and accurate RP-HPLC method was developed and validated for rapid assay of Eszopiclone (ESZ) in bulk and in tablet dosage form. Isocratic elution at a flow rate of 1 ml/ min was employed on a Phenomenax Luna C₁₈ column (150×4.6 mm; 5 μ) at ambient temperature. The mobile phase consisted of Acetonitrile: phosphate buffer adjusted to pH 2.5 (25:75% v/v). The UV detection wavelength was 304 nm and 20 μl of sample was injected. The retention time for ESZ was 3.92 min. The method obeys Beer's law in the concentration range of 4-24 μg/ml. The amount of Eszopiclone Present in the formulation was found to be 99.60±1.5389. The % recovery was in the range between 99.25% and 99.86%. The percentage RSD for precision and accuracy of the method was found to be less than 2%. The method was validated as per the standard analytical procedures and statistical parameters. The method was successfully applied for routine analysis of ESZ in bulk and in formulation.