Current Issue : July - September Volume : 2018 Issue Number : 3 Articles : 5 Articles
The aim of this study was to develop and validate a fast and simple reversed-phase HPLC\nmethod for simultaneous determination of four cardiovascular agentsââ?¬â?atorvastatin, simvastatin,\ntelmisartan and irbesartan in bulk drugs and tablet oral dosage forms. The chromatographic\nseparation was accomplished by using Symmetry C18 column (75 mm Ã?â?? 4.6 mm; 3.5 Ã?¼) with a\nmobile phase consisting of ammonium acetate buffer (10 mM; pH 4.0) and acetonitrile in a ratio\n40:60 v/v. Flow rate was maintained at 1 mL/min up to 3.5 min, and then suddenly changed to\n2 mL/min till the end of the run (7.5 min). The data was acquired using ultraviolet detector monitored\nat 220 nm. The method was validated for linearity, precision, accuracy and specificity. The developed\nmethod has shown excellent linearity (R2 > 0.999) over the concentration range of 1ââ?¬â??16 Ã?¼g/mL.\nThe limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.189ââ?¬â??0.190\nand 0.603ââ?¬â??0.630 Ã?¼g/mL, respectively. Inter-day and intra-day accuracy and precision data were\nrecorded in the acceptable limits. The new method has successfully been applied for quantification of\nall four drugs in their tablet dosage forms with percent recovery within 100 Ã?± 2%....
Chemical composition and porosity characteristics of calcium silicate-based endodontic cements are important determinants of\ntheir clinical performance. Therefore, the aim of this study was to investigate the chemical composition and porosity characteristics\nof various calcium silicate-based endodontic cements: MTA-angelus, Bioaggregate, Biodentine, Micromega MTA, Ortho\nMTA, and ProRoot MTA. The specific surface area, pore volume, and pore diameter were measured by the porosimetry analysis of\nN2 adsorption/desorption isotherms. Chemical composition and powder analysis by scanning electron microscope (SEM) and\nenergy dispersive spectroscopy (EDS) were also carried out on these endodontic cements. Biodentine and MTA-angelus showed\nthe smallest pore volume and pore diameter, respectively. Specific surface area was the largest in MTA-angelus. SEM and EDS\nanalysis showed that Bioaggregate and Biodentine contained homogenous, round and small particles, which did not contain\nbismuth oxide....
The objective of this investigation was to study the degradation behavior and kinetics of the difluprednate from ophthalmic emulsion under different ICH recommended stress condition by validated stability indicating LC method for quantification of potential known and unknown degradation product. Chromatographic separation was achieved on the C-18 stationary phase with a gradient elution using a mobile phase A consisting of ammonium formate (pH 4.5 ±005 adjusted with formic acid) and acetonitrile (ACN) as mobile phase B. The detection was carried out by UV-PDA detector at 240 nm with a flow rate of 1.5 ml/min and run time of 36 min. Developed RP-HPLC method was validated for accuracy (recovery), precision, linearity, specificity, robustness (deliberate change in pH, Flow rate and column oven temperature) and limit of detection and quantification in accordance with ICH guidelines (Q2 R1). To study the degradation behavior, difluprednate were subjected under hydrolysis (acidic and alkaline), oxidative, thermal and photolytic stress conditions. Degradation products were well resolved from the difluprednate. Moreover, the kinetics of the acid, alkaline, peroxide, thermal and photolytic degradation of the difluprednate was investigated. Different order of kinetic plots were constructed and found that zero order kinetic plots fits to calculate the degradation rate constant, half life and shelf life of difluprednate....
A simple, sensitive, and reliable reversed-phase, Ultra-High-Pressure Liquid\nChromatography (UHPLC) coupled with a Diode Array Detector (DAD) method for the simultaneous\ndetermination of Procainamide (PA) and its major metabolite, N-acetylprocainamide (NAPA), in rat\nplasma was developed and validated. A simple deproteinization method with methanol was applied\nto the rat plasma samples, which were analyzed using UHPLC equipped with DAD at 280 nm, and a\nSynergiââ??¢4 Ã?¼m polar, reversed-phase column using 1% acetic acid (pH 5.5) and methanol (76:24, v/v)\nas eluent in isocratic mode at a flow rate 0.2 mL/min. The method showed good linearity (r2 > 0.998)\nover the concentration range of 20ââ?¬â??100,000 and 20ââ?¬â??10,000 ng/mL for PA and NAPA, respectively.\nIntra- and inter-day accuracies ranged from 97.7 to 110.9%, and precision was <10.5% for PA and\n99.7 to 109.2 and <10.5%, respectively, for NAPA. The lower limit of quantification was 20 ng/mL for\nboth compounds. This is the first report of the UHPLC-DAD bioanalytical method for simultaneous\nmeasurement of PA and NAPA. The most obvious advantage of this method over previously reported\nHPLC methods is that it requires small sample and injection volumes, with a straightforward,\none-step sample preparation. It overcomes the limitations of previous methods, which use large\nsample volume and complex sample preparation. The devised method was successfully applied to the\nquantification of PA and NAPA after an intravenous bolus administration of 10 mg/kg procainamide\nhydrochloride to rats....
Perindopril arginine and Indapamide hemihydrate in combination were proven to have\na synergistic antihypertensive impact when compared with the use of each component alone.\nTherefore, a new Ultra-High Performance Liquid Chromatography coupled with Ultraviolet\ndetector (UHPLC-UV) method has been developed and subsequently validated for simultaneous\ndetermination of the anti-hypertensive combination of Perindopril arginine and Indapamide\nhemihydrate. The separation of Perindopril arginine and Indapamide hemihydrate was achieved\nusing a BEH C18 (1.7 Ã?¼m, 2.1 Ã?â?? 50 mm) analytical column (WatersÃ?® Acquity UPLC) and a mobile\nphase composed of 0.01% v/v formic acid in water adjusted to pH 4 with acetic acid and acetonitrile\n(40:60 v/v). The method was able to separate Perindopril arginine and Indapamide hemihydrate\nwithin less than 4.5 min with high accuracy, precision, resolution, and sensitivity. The content\nof Perindopril arginine and Indapamide hemihydrate present in the dosage form Coversyl PlusÃ?®\n(5000 Ã?¼g of Perindopril arginine/1250 Ã?¼g of Indapamide hemihydrate) was determined in triplicate\nto give a concentration of 4991 Ã?¼g and 1247 Ã?¼g, respectively, from the manufacturerââ?¬â?¢s stated amounts\nwith Relative Standard Deviation (%RSD) of Ã?±0.63% for Perindopril arginine and Ã?±0.84% for\nIndapamide hemihydrate. Moreover, the degradation products of the combination were elucidated\nby UHPLC-Quadrupole Time of Flight-Mass spectrometry (UHPLC-QToF-MS) under acidic, basic,\nand thermal conditions. In conclusion, the developed UHPLC-UV method was sensitive, rapid,\nand precise. Furthermore, forced degradation studies were performed and the degradants were\nidentified by UHPLC-Electro-Spray Ionization-QToF (UHPLC-ESI-QToF)....
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