LC–MS/MS Determination of Antihypertension Drugs in Rat Plasma and Urine: Applications to Pharmacokinetics

Determination of active ingredients in antihypertensive drugs using a novel green HPLC method approach

A novel, sensitive, fast, and pratic RP-HPLC methods were presented for the quantitative amounts of Telmisartan (TEL) and Olmesartan (OLM) in the presence of Amlodipin (AML) in a binary mixture of pharmaceutical preparation. Waters Spherisorb ODS-2 C18 column was used for separation. These methods were valid over linearity ranges of 2.5-30 μμg/mlL, 2-85 μμg/mlL, and 2-35 μμg/mlL for OLM, TEL, and AML, respectively. The mobile phase system consisted of acetonitrile:methanol: phosphate buffer at pH 3.0 (65:5:30 v/v/v), and the flow rate was 1,5 mlL/min for OLM and AML. The mobile system's other mixture (TEL and AML) was acetonitrile:methanol: phosphate buffer at pH 2.5 (65:5:30 v/v/v), and the flow rate was 1,5 mlL/min. These procedures were successfully applied to bulk, laboratory synthetic mixture, and medicinal dosage forms to use active ingredients quantitatively. The studied methods were validated according to ICH guidelines. In the developed HPLC method, the limit of detection values was found to be 0.020 μμg/mlL for TEL, 0.025 μμg/mlL for OML, and 0.070 μμg/mlL for AML. The correlation coefficients for the HPLC method were found to be 0.9938 for TEL, 0.9996 for OML, and 0.9982 for AML. The calibration range is between 2.5 and -30, 5-35, and 2-85 μμg/mlL for OLM, AML, and TEL, respectively. The proposed HPLC method is a convenient, effective, sensitive, green, and time-saving method for the rapid determination of TEL and OLM in the presence of AML.

A vinylpyrrolidone-based thin film microextraction in combination with direct solid-state spectrofluorimetry for determination of sartans in human plasma

A vinylpyrrolidone-ethylene glycol dimethacrylate-acrylic acid thin film was prepared on a polypropylene guard and its formulation was optimized for application in thin film microextraction followed by direct solid-state spectrofluorimetry method. The surface morphology, fluorescence property and extraction performance of the thin film were investigated systematically. The intra- and inter-batch reproducibilities of thin film fabrication were obtained 2.3 and 4.2%, respectively. The lifetime of each prepared thin film was 30 times with a relative standard deviation of less than 1.4%. The developed method was optimized for extraction of some sartans as angiotensin II receptors antagonist (including losartan, valsartan, and olmesartan) which have been used to control hypertension as the main causes of cardiovascular disease. The optimum extraction conditions achieved at 2- (for losartan) and 4- (for valsartan and olmesartan) sample pH, 500-rpm rotation rate and 30-min extraction time for all three analytes. At the optimum conditions, analyses of losartan, valsartan, and olmesartan were validated in the human plasma matrix. Broad linearity ranges with determination coefficients of more than 0.999 were achieved for each calibration curve. Limit of detection of the method was 0.5 ng mL^-1 for all three analytes. The intra- and inter-day accuracies and precisions of the developed method were evaluated in spiked plasma samples at three concentration levels of each analyte with high recoveries of 95-101% and relative standard deviations less than 6%. This method provides a simple, sensitive, fast, and high-throughput analysis method with the possibility of effective extraction of at least 40 samples simultaneously without the necessity of protein precipitating, desorption, and solvent evaporation steps.