Stability-indicating RP-HPLC method for analysis of eplerenone in the bulk drug and in a pharmaceutical dosage form

Abstract

Summary A novel stability-indicating reversed-phase (RP) HPLC method has been developed and validated for quantitative analysis of eplerenone in the bulk drug and in a pharmaceutical dosage form. Use of a 250 mm × 4.6 mm, 5-μm particle, C18 column with 55:45 (v/v) 50 mM ammonium acetate buffer (pH 7)-acetonitrile as isocratic mobile phase enabled separation of the drug from its degradation products. UV detection was performed at 240 nm. The method was validated for linearity, accuracy (recovery), precision, specificity, and robustness. The linearity of the method was excellent over the range 10–100 μg mL−1 (correlation coefficient 0.999). The limits of detection and quantification were 0.019 and 0.053 μg mL−1, respectively. Recovery of eplerenone from the pharmaceutical dosage form ranged from 100.97 to 101.25%. Eplerenone was subjected to stress conditions (hydrolysis (acid, base), oxidation, photolysis, and thermal degradation) and the stressed samples were analysed by use of the method. Degradation was observed in acid, base, and 30% H2O2. The drug was stable under the other stress conditions investigated. The degradation products were well resolved from main peak. The forced degradation studies prove the stability indicating power of the method.