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An isocratic reversed-phase high-performance liquid chromatographic method has been developed and validated for the simultaneous determination of aspirin, prasugrel HCl and clopidogrel bisulfate in the presence of clopidogrel-related compound (impurity-A) in focus on counterfeit. This method was used to determine counterfeited antiplatelet drugs in two substandard Indian pharmaceutical products sold on the market in Yemen and two traditional herbal medicines sold on the market in China. Thin layer chromatography and mass spectrometry of counterfeit herbal medicines have additionally been carried out to verify the identification of adulterants. Chromatographic separation was performed on Inertsil ® ODS-3 C18 (4.6 × 250 mm, 5 μm) with isocratic mobile phase elution containing a mixture of acetonitrile: (25 mM) potassium dihydrogen phosphate buffer, pH 2.7 adjusted with 0.1 M o -phosphoric acid (79: 21, v/v), at a flow rate of 1 mL/min and UV detection at 220 nm. Designs of experiment methodology, Plackett–Burman and Box–Behnken designs were used for the screening and optimization of the mobile phase composition. The method validation was also performed in accordance with the International Council on Harmonization (ICH) guidelines. The method developed for routine analysis was found to be sensitive, simple, accurate and highly robust. The results were statistically compared to reference methods using Student's t -test and variance ratio F -test at P  < 0.05. [ABSTRACT FROM AUTHOR]

Aspirin (ASP) and cilostazol (CST) are used as a combination in pharmaceutical formulations for treatment of strokes. Salicylic acid (SAL) is considered to be one of the main synthesis impurities and a degradation product of ASP. On the other hand, the main related impurities of CST are CST related A, B, and C (CST-RA, CST-RB, and CST-RC), respectively. Furthermore, as high efficiency and less elution are the basic requirements of high-speed chromatographic separation, so, a comparative study of two simple, precise, and accurate reversed-phase HPLC and UPLC methods was developed and validated for simultaneous estimation of ASP and CST in bulk and capsules in the presence of SAL, CST-RA, CST-RB, and CST-RC. A Eurospher II C18 (250 × 4.6 mm2, 5 µm) for HPLC method and an Agilent Zorbax Eclipse Plus C18 (50 × 2.1 mm2, 1.8 µm) for UPLC method were used. A gradient mobile phase of 20 mM anhydrous KH2PO4buffer solution (containing 0.2% triethylamine (TEA), v/v) with pH adjusted to 2.9 using orthophosphoric acid (solution A) and acetonitrile (solution B) mixed in different proportions for HPLC and UPLC methods was prepared. Flow rate was set to 1.0 and 0.3 mL min−1for HPLC and UPLC methods, respectively, and the detection was performed for both methods at 210 nm. It worth noting that the proposed UPLC-DAD assay exhibited relatively much more precision, sensitivity, specificity, and economic and chromatographic separation superiority than proposed HPLC-UV assay. Both developed methods were compared with reference methods to prove its applicability and are suitable for purity assessment of ASP and CST in bulk and capsules. [ABSTRACT FROM PUBLISHER]