The present work describes a validated reverse phase high performance liquid chromatographic method for simultaneous estimation of telmisartan and hydrochlorothiazide in tablet formulation. Chromatography was performed on a ODS Hypersil C18 (25 cm×4.6 mm I.D) column from thermo in isocratic mode with mobile phase containing acetonitrile:0.05 M KH 2 PO 4 pH 3.0 (60:40). The flow rate was 1.0 ml/min and the eluent was monitored at 271 nm. The selected chromatographic conditions were found to effectively separate telmisartan (RT-5.19 min) and hydrochlorothiazide (RT-2.97 min). Linearity for telmisartan and hydrochlorothiazide were found in the range of 4.1-20.48 µg/ml and 1.28-6.4 µg/ml, respectively. The proposed method was found to be accurate, precise, reproducible and specific and can be used for simultaneous analysis of these drugs in tablet formulation.

The present work describes a two-wavelength method for simultaneous determination of metoprolol and hydrochlorthiazide in fixed dose combination tablet. The wavelengths selected for method were 257.8 nm, 282.9 nm and 315.0 nm. The absorbance difference at first two wavelengths was used for determination of metoprolol and the latter was used for determination of hydrochlorthiazide. The recovery value for the drugs from the tablet matrix was found to be 100.55% (metoprolol) and 99.97% (comparison with standard) and 98.09% (E1%, 1cm) for hydrochlorthiazide. The method has an advantage that hydrochlorthiazide can be estimated in combination, as there is no interference of metoprolol at 315.0 nm. The method was evaluated statistically for its accuracy and precision.

A simple, fast, precise multicomponent mode analysis method has been developed for simultaneous estimation of ranitidine and domperidone in tablet formulation. The sampling wavelengths selected for both the drugs were 229 nm, 245 nm, 270 nm, 285 nm, 294 nm on trial-and-error basis using methanol as solvent. The linearity for both the drugs at all the selected wavelengths lies between 3.0 and 50 µg/ml for ranitidine and 0.2 and 3.5 µg/ml for domperidone. The concentrations of both the drugs were evaluated in laboratory mixture and marketed formulation. The recovery study was carried out by standard addition method.

A simple and rapid RP-HPLC method has been developed and validated for the simultaneous determination of Levocloperastine fendizoate and Chlorpheniramine maleate syrup formulation. Resolution of the analytes was achieved within 10min, employing a mixture of 10mM mobile phase Buffer (pH 6.5): Acetonitrile (50:50, % v/v) as isocratic mobile phase, pumped at 1.0mL/ min through a C18 column (5µm particle size). The detection wavelength for the analytes was 227nm. The system suitability parameters were found to be acceptable. The linearity of response (r 2 >0.999) in the appropriate ranges (from 50% up to 150% of the expected concentrations of the analytes in the formulations), method accuracy (RSD<2.0%), repeatability and intermediate precision (RSD<2.0%), were confirmed. Robustness result indicates that the methods performance can withstand small variations in method parameters. Satisfactory results obtained in terms of analyte recovery and RSD, while analyzing marketed pharmaceutical preparations. Hence the method can be useful for regular analysis of this combination in marketed syrup formulation.