Validated Stability Indicating RP-HPLC Method for Simultaneous Estimation of Codeine Phosphate and Chlorpheniramine Maleate from Their Combined Liquid Dosage Form

The present paper describes the development of quick stability indicating RP-HPLC method for the simultaneous estimation of codeine phosphate and chlorpheniramine maleate in the presence of its degradation products, generated from forced degradation studies. The developed method separates codeine phosphate and chlorpheniramine maleate in impurities/degradation products. Codeine phosphate and chlorpheniramine maleate and their combination drug product were exposed to acid, base, oxidation, dry heat, and photolytic stress conditions, and the stressed samples were analysed by proposed method. The proposed HPLC method utilizes the Shimadzu HPLC system on a Phenomenex C18 column (, 5 μ) using a mixture of 1% o-phosphoric acid in water : acetonitrile : methanol (78 : 10 : 12) mobile phase with pH adjusted to 3.0 in an isocratic elution mode at a flow rate of 1 mL/min, at 23°C with a load of 20 μL. The detection was carried out at 254 nm. The retention time of codeine phosphate and chlorpheniramine maleate was found to be around 3.47 min and 9.45 min, respectively. The method has been validated with respect to linearity, robustness, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ). The developed validated stability indicating HPLC method was found to be simple, accurate, and reproducible for the determination of instability of these drugs in bulk and commercial products