K. Valliappan

Development of a HPLC method for the simultaneous determination of losartan potassium and atenolol in tablets

A new reversed-phase high performance liquid chromatography method was developed and validated for the simultaneous determination of losartan potassium and atenolol in tablets. The separation was achieved on Supelcosil ODS analytical column (25×0.46 cm, i.d., 5 µm) using acetonitrile and 25 mM potassium dihydrogen phosphate (45:55 v/v, pH 3.00±0.05) as mobile phase at a flow rate of 1.2 ml/min. Detection was carried out using a UV detector at 227 nm. The method was validated. The developed and validated method was successfully applied for the quantitative analysis of Losar beta® tablets. The total chromatographic analysis time per sample was about 6 min with atenolol, chlorzoxazone (internal standard) and losartan eluting at retention times of about 2.72, 4.89 and 5.61 min, respectively. The standard curves were linear over the concentration ranges, 1 to 10 µg/ml for losartan potassium and atenolol. The values obtained of LODs were 0.029 and 0.062 µg/ml and LOQs were 0.078 and 0.187 µg/ml for losartan potassium and atenolol, respectively. The proposed method is fast, accurate and precise for the determination of losartan potassium and atenolol for routine quality control of tablets containing these two drugs.

Direct Chiral HPLC Method for the Simultaneous Determination of Warfarin Enantiomers and Its Impurities in Raw Material and Pharmaceutical Formulation: Application of Chemometric Protocol

Warfarin is a well-known anticoagulant agent that occurs in two enantiomers, (R)-(+)-warfarin and (S)-(−)-warfarin, in which 4-hydroxycoumarin and benzalacetone are commonly found as impurities. Due to the lack of analytical reports for the simultaneous estimation on warfarin and its impurities in bulk drug and pharmaceuticals, we aim at the simultaneous estimation and optimization of the chromatographic separation of warfarin and its related substances employing experimental design. Central composite design was employed to evaluate the influence of two independent variables (concentration of organic modifier and flow rate) on the output responses: capacity factor (k1), resolution of the peak (Rs3,4), and retention time of the last peak (tR5), as well as to model these responses. Further, the central composite design results were combined in a multicriteria decision-making approach in order to obtain a set of optimal experimental conditions leading to the most desirable compromise between resolution and analysis time.