Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
A reversed-phase liquid chromatographic separation with pulsed amperometric detection of phenolic acids at a glassy carbon electrode is\ndescribed. Chromatographic separation was carried out in isocratic conditions using 0.20 molÃ?·LâË?â??1 acetic acid (pH 5.0)/water (80 : 20, v/v)\nas mobile phase under constant working potential mode of 0.80 V. Chromatographic peaks presented high resolution and separation.\nCalibration curves exhibited excellent correlation coefficients, above 0.995. Linear ranges of the analytes, in mg LâË?â??1, were of 0.018ââ?¬â??18\n(gallic acid), 0.146ââ?¬â??19 (vanillic acid), 0.13ââ?¬â??17 (caffeic acid), 0.016ââ?¬â??16 (ferulic acid), and 0.008ââ?¬â??17 (p-coumaric acid), respectively. Limits of\ndetection ranged from 1.6 to 97 Ã?¼gÃ?·LâË?â??1 and precision varied in 1.73ââ?¬â??3.78% interval. Concentrations of 19Ã?±0.51mgÃ?·LâË?â??1 and 7.8Ã?±\n2.5mgÃ?·LâË?â??1 were found for vanillic and caffeic acids, respectively, in a sugarcane vinasse sample. Gallic, ferulic, and p-coumaric acids were\nnot detected. Recovery results demonstrated that the proposed method is accurate, and it can be used to detect and quantify phenolic\nacids in sugarcane vinasse without any influence of interferents....
A study was carried out to investigate compatibility of amlodipine besylate and olmesartan medoxomil with a variety of\npharmaceutical excipients. Both drugs are antihypertensive agents that can be administered alone, in monotherapy, or in\npharmaceutical association. The studies were performed using binary and ternary mixtures, and samples were stored for 3 and 6\nmonths at 40Ã?°C under 75% relative humidity and dry conditions. For this study, a method based on high-performance liquid\nchromatography (HPLC) was developed and validated for the simultaneous determination of amlodipine besylate and olmesartan\nmedoxomil in samples from pharmaceutical preformulation studies using diode array detector (DAD) and charged aerosol\ndetector (CAD). The runtime per sample was 10 min with retention time of 7.926 min and 4.408 min for amlodipine and\nolmesartan, respectively. The validation was performed according to ICH guidelines. The calibration curve presents linear\ndynamic range from 12 to 250 Ã?¼g mLâË?â??1 for amlodipine and from 25 to 500 Ã?¼g mLâË?â??1 for olmesartan with coefficient of determination\n(R2 ââ?°Â¥ 0.9908) while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.0%.\nThe excipients such as corn starch, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, talc, polyvinylpyrrolidone,\nlactose monohydrate, and polyethylene glycol showed potential incompatibilities after accelerated stability testing...
The aim of the present study was the development and validation of a simple, precise and specific RP-HPLC method for assay of montelukast (MNT) and rupatadine (RPT) in tablet dosage forms. The separation was achieved on Grace C-18 Column (4.6 × 250 mm, 5 μm) using acetonitrile and 0.05% OPA (60:40, v/v) as mobile phase for assay and flow rate 1 ml/ min and detection was carried out in U.V detector at 242.0 nm. The retention time of RPT and MNT were found to be 3.86 min and 7.60 min respectively. The linearity of the RPT and MNT was found over the range of 5-25 μg/ml. The system suitability test shows the response with retention time, theoretical plate, tailing factor and peak area for both the drugs. The validation of method carried out using ICH guidelines. The developed method was gave good resolution for drugs. The developed RP-HPLC method can be applied for routine quantitative and qualitative analysis of RPT and MNT in bulk and pharmaceutical formulations like tablets....
New spectrophotometric and chemometric methods were carried out for the simultaneous assay of trelagliptin (TRG) and its acid\ndegradation product (TAD) and applied successfully as a stability indicating assay to recently approved ZafatekÃ?® tablets. TAD was\nmonitored using TLC to ensure complete degradation. Furthermore, HPLC was used to confirm dealing with one major acid\ndegradation product. The proposed methods were developed by manipulating zero-order, first-derivative, and ratio spectra of\nTRG and TAD using simultaneous equation, first-derivative, and mean-centering methods, respectively. Using Spectra Manager\nII and Minitab v.14 software, the absorbance at 274 nmââ?¬â??260.4 nm, amplitudes at 260.4 nmââ?¬â??274.0 nm, and mean-centered values at\n287.6 nmââ?¬â??257.2nm were measured against methanol as a blank for TRG and TAD, respectively. Linearity and the other validation\nparameters were acceptable at concentration ranges of 5ââ?¬â??50 Ã?¼g/mL and 2.5ââ?¬â??25 Ã?¼g/mL for TRG and TAD, respectively. Using oneway\nanalysis of variance (ANOVA), the optimized methods were compared and proved to be accurate for the simultaneous assay\nof TRG and TAD....
A simple RP-HPLC method was developed and chemometric designs were applied for the simultaneous estimation of\nbacoside A3 (BA3), piperine (PPN) and crocin (CON) in polyherbal formulation brahmi vati. The separation was carried out by\nusing phenomenex C18 column (15 cm ââ?¬Â¢ 4.6 mm id, 5 Ã?¼m particle size). For the optimization the ranges of independent variables\nused were MeCN: 33ââ?¬â??38%, buffer conc.: 10ââ?¬â??20 mM and flow rate: 1ââ?¬â??2 ml/min. The data generated from the chromatograms\nwere mined by using chemometric methods such as trilinear regression analysis and cramerââ?¬â?¢s matrix method. The wavelengths\nselected for all the above methods were 248 nm (wavelength of maximum absorption; Ã?»max of BA3), 261 nm (wavelength of\nmaximum absorption; Ã?»max of PPN) and 274 nm (wavelength of maximum absorption; Ã?»max of CON). The method holds good\nlinearity for BA3 from 05-25 Ã?¼g/ml, for PPN from 10-50 Ã?¼g/ml and CON from 03-15 Ã?¼g/ml with regression coefficient values of\n0.999, 0.999 and 0.998 respectively. The intraday and inter-day precision was found to be less than 2% RSD. The percentage\nrecovery and percentage assay was in the range of 95-105% for bacoside A3 (BA3), piperine (PPN) and Crocin (CON) by all the\nmethods. The developed method neither requires any cumbersome separation procedure nor complex derivatization\nprocedures for the analysis of the three herbal drugs and moreover they are effective in minimizing the errors in analysis,\nsimple and economical....
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