Current Issue : April - June Volume : 2015 Issue Number : 2 Articles : 7 Articles
A method is described here for the simultaneous determination of retinol, ?-tocopherol, lycopene, and ?-carotene in human plasma. The effectiveness of various protein precipitants and extraction solvents was tested. After adequate sample preparation, the samples were injected directly into the HPLC system. The separation was realized on an analytical reversed-phase column with a UV-Vis detection. The analytical performance of this method was satisfactory. The intraassay and interassay coefficients of variation were below 10%. The recoveries were as follows: 97.0% (CV 2.4%) for retinol, 94.6% (CV 1.7%) for ?-tocopherol, 91.9% (CV 3.6%) for lycopene, and 93.9% (CV 4.2%) for ?-carotene. The levels of selected fat-soluble vitamins in plasma of patients with cardiovascular disease were measured and discussed....
A simple, rapid, and selective RP-HPLC method was developed for the estimation of acyclovir in human plasma. The method\ninvolves a simple protein precipitation technique. Chromatographic separation was carried out on a reverse phase C18 column\nusing mixture of 5mM ammonium acetate (pH 4.0) and acetonitrile (40 : 60, v/v) at a flow rate of 1.0 mL/min with UV detection\nat 290 nm. The retention time of acyclovir was 4.12 minutes. The method was validated and found to be linear in the range of\n25.0ââ?¬â??150.0 ng/mL.Validation studies were achieved by using the fundamental parameters, including accuracy, precision, selectivity,\nsensitivity, linearity and range, stability studies, limit of detection (LOD), and limit of quantitation (LOQ). It shows recovery at\n91.0% which ismore precise and accurate compared to the other method. These results indicated that the bioanalytical method was\nlinear, precise, and accurate. The new bioanalytical method was successfully applied to a pharmacokinetic linearity study in human\nplasma....
A simple, precise and specific reverse phase high performance liquid chromatographic method has been developed and validated for the determination of sitagliptin in blood. The HPLC separation was carried out by reverse phase chromatography on Shimadzu HPLC system consisted of welchrom 5µ C18 column (250 X 4.6 mm), SPD 10A UV detector and LC 10AD Pumps. Rheodyne injector with 20 μl capacity, mobile phase comprises of Methanol: Water (65:35) pH 9.0 adjusted with triethanolamine at flow rate 1.0 ml/min. Glimperide was used as internal standard in the determination. The retention time of sitagliptin and internal standard was found to be 5.73 and 12.2 respectively. The detection was monitored at 262 nm. The calibration curve for sitagliptin was linear from 0.1-10 µg/ml with correlation coefficient of 0.999. The inter-day and intraday precision was found to be within limits. The method was validated as per the guidelines....
A LC-MS/MS method for determination of stavudine in human plasma was established and validated, and it was applied to the\npharmaceutical formulations bioequivalence study. 0.5mL plasma sample was extracted by liquid-liquid extraction. Stavudine\nwas detected by a LC-MS/MS system. The pharmacokinetic parameters of stavudine in different formulations were calculated by\nnoncompartmentmodel statistics.Themethod was linear over the concentration ranges 5.00ââ?¬â??1000 ng/mL in plasma.Theintra- and\ninterassay relative standard deviation (RSD) was <10%. The average accuracies for the assay at three concentrations (5.00, 80.0, and\n900 ng/mL) were from100.2% to 102.5%. Pharmacokinetic parameters of stavudine reference formulation were obtained as follows:\n????max was 0.6 Ã?± 0.2 h, ????max was 480.7 Ã?± 150.9 g/L, t1/2 was 1.7 Ã?± 0.4 h, and AUC0????? was 872.8 Ã?± 227.8 g?h/L, and pharmacokinetic\nparameters of stavudine test formulationwere obtained as follows: ????max was 0.5Ã?±0.2 h, ????max was 537.5Ã?±178.5 g/L, t1/2 was 1.7Ã?±0.3 h,\nand AUC0????? was (914.1 Ã?± 284.5) g?h/L. Calculated with AUC0?????, the bioavailability of two formulations was 105.0%....
A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine\nblonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS) was established. A simple direct protein\nprecipitation method was used for the sample pretreatment, and chromatographic separation was performed on aWaters XBridge\nC8 (4.6 Ã?â?? 150 mm, 3.5 ????m) column. The mobile phase consists of a mixture of 10mM ammonium formate and 0.1% formic acid\nin water (A) and 0.1% formic acid in methanol (B). To quantify blonanserin, blonanserin C, and IS, multiple reaction monitoring\n(MRM) was performed in positive ESI mode. The calibration curve was linear in the concentration range of 0.012ââ?¬â??5.78 ng?mL?1\nfor blonanserin and 0.023ââ?¬â??11.57 ng?mL?1 for blonanserin C (????2 > 0.9990). The intra- and interday precision of three quality control\n(QC) levels in plasma were less than 7.5%. Finally, the current simple, sensitive, and accurate LC-MS/MS method was successfully\napplied to investigate the pharmacokinetics of blonanserin and blonanserin C in healthy Chinese volunteers....
In vitro interaction of sildenafil citrate (SC) with bovine serum albumin (BSA) was investigated at\ntwo excitation wavelengths of BSA (280 nm and 293 nm) at two different temperatures (298 K and\n308 K) by fluorescence emission spectroscopy. The study showed that quenching of BSA fluorescence\nby sildenafil citrate was the result of formation BSA-SC complex with probable involvement\nof both tryptophan and tyrosine residues of BSA. Fluorescence quenching constant was determined\nfrom Stern-Volmer equation, and both static quenching and dynamic quenching were showed for\nBSA by SC at the conditions. Van�t Hoff equation was used to measure the thermodynamic parameters\nG, H, and S at the temperatures which indicated that the hydrogen bond and the hydrophobic\nforces played major roles for BSA-SC complexation. The binding number (n) was found\nto be indicating that one mole BSA bound with one mole SC. The binding affinity of SC to BSA\nwas calculated at different temperatures. The binding constant was decreased with increasing\ntemperatures indicating that stability of BSA-SC complex decreased with increasing temperatures....
In this study, a sensitive, simple, and reliable HPLC method for quantification of pregabalin in human plasma was developed and\nvalidated. 1-Fluoro-2,4-dinitrobenzene was used as precolumn derivatization agent. For chromatography, an analytical reversed\nphase (C18) column and a mixture of Na2HPO4 10mM(pH 8.0)ââ?¬â?methanol (35 : 65 v/v) were used as stationary and mobile phase,\nrespectively. Detection was performed using a UV detector tuned at 360 nm. The linearity of the method was tested over the\nconcentration range 1ââ?¬â??4500 ng/mL in 500 ????L of human plasma and satisfactory results were obtained (r2 > 0.999). The method\nshowed good precision and accuracy in terms of withinââ?¬â?between days relative standard deviations and percent deviation from\nnominated values (in the range of 4.3ââ?¬â??12.7% and 2.6ââ?¬â??8.0%, resp.).Thelimit of quantification of the method was found to be 1 ng/mL\nwhich is better than previously reported method and indicates its potential application for sensitive bioanalysis...
Loading....