Abstract
A stability-indicating assay method has been developed and subsequently validated for the simultaneous estimation of aspirin, atorvastatin and clopidogrel in active pharmaceutical ingredient and commercial dosage form. The proposed reverse phase liquid chromatographic method was performed phenomenex ® Gemini C18 column (150 x 4.6 mm i.d., 5 µm) and mobile phase consisting of Acetonitrile: Methanol: 0.1% TEA (pH 3.0 adjusted with ortho phosphoric acid) in a ratio of 52: 05: 43 (v/v/v) at a flow rate of 1.4 ml/min. The detection was carried out by photodiode array detector at the wavelength of 220 nm based on the peak area with linear calibration curves established at concentration of 2-10 µg/ml for aspirin,clopidogrel and 1-5 µg/ml for atorvastatin (where R2> 0.999 for all three drugs). The method was validated in terms of accuracy, precision, linearity, LOD, LOQ and robustness. This method has been successively applied for commercial marketed formulation and there is no interference from the excipients. Aspirin, atorvastatin and clopidogrel their combination drug product were exposed to acid, alkali and neutral hydrolysis, oxidation, dry heat and photolytic stress conditions and the stressed samples were analyzed by the proposed method. As this method could effectively separate the drug from its degradation products, it can be employed as stability indicating method for the determination of instability of these drugs in bulk and pharmaceutical dosage form.
