A simple and sensitive high performance liquid chromatographic method (HPLC) and direct flow injection analysis method (FIA) are described for the determination of trimetazidine HCl (TMZ) in tablets. A mobile phase consisting of methanol:0.02 mol center dot L -1 potassium dihydrogen phosphate:0.005 mol center dot L -1 sodium dihydrogen phosphate (62:5:33 v/v/v) was used for the resolution of the compound on a reversed phase column for HPLC. For the FIA method; the best solvent system was found to be consisting of methanol:water (10:90 v/v). A flow rate of 1.2 mL center dot min(-1) was pumped and active material was detected at 210 nm. Limit of detection (LOD) and limit of quantitation (LOQ) values were found to be 1.2x10 -7 mol center dot L-1 and 3.5x10(-7) mol center dot L-1 , respectively, for HPLC. LOD and LOQ values were found to be 2.35x10 -7 mol center dot L-1 and 7.04x10(-7) mol center dot L-1 , respectively for FIA. The results obtained from the analysis of TMZ tablet formulations were comparable using both methods.

A simple, precise, rapid, and accurate reversed-phase high performance liquid chromatographic (RP-HPLC) method has been developed for the determination of sildenafil citrate (SLD) in pharmaceutical dosage forms and spiked human plasma. Chromatography was carried out on a C-18 reversed-phase column, using a mixture of acetonitrile:water(45:55, v/v) as a mobile phase at a flow rate of 1 mL . min(-1). Phenobarbital sodium was used as an internal standard (IS) and detected using a diode array detector at 220 nm. Retention times of SLD and IS were 7.2 and 3.2 min, respectively. The linear range of SLD was found to be 5 x 10(-8)-1 X 10(-5)mol . L-1. Limit of quantitation (LOQ) and limit of detection (LOD) were calculated to be 7.5 x 10(-8) and 2.2 x 10(-8) mol . L-1, respectively. The method was validated for its linearity, precision, accuracy, stability, robustness, and ruggedness. The proposed method was applied to sildenafil tablets and spiked human plasma. In addition, the results were compared with those obtained from UV-spectrophotometry.

Pravastatin (PRA) is an inhibitor of HMG-CoA reductase enzyme, which is clinically used as a hypolipidemic agent to reduce cholesterol level. A capillary electrophoretic method for the determination of PRA in pharmaceutical tablet formulations is described. PRA and lansoprazole as an internal standard (IS) were well migrated in the background electrolyte of 10 mM borate buffer (pH 8.5) and 10% acetonitrile using a fused silica capillary. The separation was achieved by applying 27.5 kV, detecting at 200 nm and injecting the sample for 0.5 s and with an average migration time (tm) for PRA and IS of 4.7 and 3.9 min, respectively, at ambient temperature. The results were precise and repeatable for areas of the peaks and peak normalization ratio (PNPRA/PNIS). Linearity was found in the concentration range of 1.56-7.78 x 10(-5) M. Intra-day and Inter-day assays were performed and reliable results were obtained. Limit of detection and limit of quantitation were 8 x 10(-6) and 2.4 x 10(-5) M, respectively. The proposed method was successfully applied for the analysis of PRA in the pharmaceutical tablet formulation. The method proved simple, precise and fast since the analysis can be performed in less than 5 min.

A flow-injection analysis (FIA) of paroxetine hydrochloride (PRX), a selective serotonin reuptake inhibitor (SSRI) currently used as an antidepressant drug, is described. A 0. 1 mol dm–3 acetate buffer at pH 3. 07 was found to be the best solvent. The analyte was detected at 293 nm. The calibration equation was linear over the range of 1. 07 × 10–6 to 5. 35 × 10–6 mol dm–3. The limit of detection (LOD) and the limit of quantitation (LOQ) were 3. 2 × 10–7 and 9. 5 × 10–7 mol dm–3, respectively. The proposed method was applied to the determination of PRX in pharmaceutical preparations. The results were compared with those obtained by a conventional batchwise UV-spectrophotometry.