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Bioanalysis of tolvaptan,a novel AVP‐V2 receptor antagonist in human plasma by a novel LC‐ESI‐MS/MS method: a pharmacokinetic application in healthy South Indian male subjects 下载免费PDF全文
Venkata Ramu Derangula Nageswara Rao Pilli Babu Rao Bhukya Chalapathi Rao Pulipati Vinayender Adireddy Venkateswarlu Ponneri 《Biomedical chromatography : BMC》2014,28(3):332-340
A simple, rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC‐ESI‐MS/MS) assay method is proposed for the determination of tolvaptan in human plasma samples using tolvaptan d7 as internal standard (IS). Analyte and the IS were extracted from 100 μL of human plasma via simple liquid–liquid extraction. The chromatographic separation was achieved on a C18 column using a mixture of methanol and 0.1% formic acid buffer (80:20, v/v) as the mobile phase at a flow rate of 1.0 mL/min. The calibration curve obtained was linear (r2 ≥ 0.99) over the concentration range of 0.05–501 ng/mL. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The intra‐day and inter‐day precision (coefficient of variation) and accuracy results in three validation batches across five concentration levels were well within the acceptance limits. A run time of 2.0 min for each sample made it possible to analyze more samples in a short time, thus increasing the productivity. The proposed method was successfully applied to a pharmacokinetic study of 15 mg and 60 mg tolvaptan tablet formulation in healthy South Indian male subjects under fasting condition. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Vinayender Adireddy Nageswara Rao Pilli Venkata Ramu Derangula Shobha Rani Satla Chinna Veera Badraiah Ganguri Venkateswarlu Ponneri 《Biomedical chromatography : BMC》2013,27(8):1062-1069
This paper describes a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry assay for the determination of aliskiren in human plasma using nevirapine as an internal standard. Analyte and the internal standard were extracted from 100 μL of human plasma via liquid–liquid extraction using tert‐butyl methyl ether. The chromatographic separation was achieved on a C18 column using a mixture of acetonitrile and 0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear (r2 ≥ 0.99) over the concentration range of 0.10–1013 ng/mL. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. A run time of 2.2 min for each sample made it possible to analyze a greater number of samples in a short time, thus increasing the productivity. The proposed method was found to be applicable to clinical studies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls 下载免费PDF全文
Dr. Shiva Adireddy Cecilia E. Carbo Taha Rostamzadeh Dr. Jose M. Vargas Prof. Leonard Spinu Prof. John B. Wiley 《Angewandte Chemie (International ed. in English)》2014,53(18):4614-4617
A facile in situ method to grow Au nanoparticles (NPs) in hexaniobate nanoscrolls is applied to the formation of plasmonic Au@hexaniobate and bifunctional plasmonic‐magnetic Au‐Fe3O4@hexaniobate nanopeapods (NPPs). Utilizing a solvothermal treatment, rigid multiwalled hexaniobate nanoscrolls and partially filled Fe3O4@hexaniobate NPPs were first fabricated. These nanostructures were then used as templates for the controlled in situ growth of Au NPs. The resulting peapod structures exhibited high filling fractions and long‐range uniformity. Optical measurements showed a progressive red shift in plasmonic behavior between Au NPs, Au NPPs, and Au‐Fe3O4 NPPs; magnetic studies found that the addition of gold in the Fe3O4@hexaniobate NPPs reduced interparticle coupling effects. The development of this approach allows for the routine bulk preparation of noble‐metal‐containing bifunctional nanopeapod materials. 相似文献
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Inside Back Cover: Peapod‐Type Nanocomposites through the In Situ Growth of Gold Nanoparticles within Preformed Hexaniobate Nanoscrolls (Angew. Chem. Int. Ed. 18/2014) 下载免费PDF全文
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Venkata Ramu Derangula Nageswara Rao Pilli Siva Kumar Nadavala Vinayender Adireddy Jaswanth Kumar Inamadugu Venkateswarlu Ponneri 《Biomedical chromatography : BMC》2013,27(6):792-801
A simple, rapid and sensitive liquid chromatography–tandem mass spectrometric (LC‐MS/MS) assay method has been developed and fully validated for the simultaneous quantification of tetrabenazine and its active metabolites α‐dihydrotetrabenazine and β‐dihydrotetrabenazine in human plasma. Tetrabenazine d7 was used as internal standard (IS). The analytes were extracted from 200 μL aliquots of human plasma via solid‐phase extraction using C18 solid‐phase extraction cartridges. The reconstituted samples were chromatographed on a Zorbax SB C18 column using a 60:40 (v/v) mixture of acetonitrile and 5 mm ammonium acetate as the mobile phase at a flow rate of 0.8 mL/min. The API‐4000 LC‐MS/MS in multiple reaction‐monitoring mode was used for detection. The calibration curves obtained were linear (r2 ≥ 0.99) over the concentration range of 0.01–5.03 ng/mL for tetrabenazine and 0.50–100 ng/mL for α‐dihydrotetrabenazine and β‐dihydrotetrabenazine. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Core‐shell structured poly(glycidyl methacrylate)/BaTiO3 nanocomposites prepared by surface‐initiated atom transfer radical polymerization: A novel material for high energy density dielectric storage 下载免费PDF全文
Muhammad Ejaz Venkata S. Puli Ravinder Elupula Shiva Adireddy Brian C. Riggs Douglas B. Chrisey Scott M. Grayson 《Journal of polymer science. Part A, Polymer chemistry》2015,53(6):719-728
Core‐shell structured barium titanate‐poly(glycidyl methacrylate) (BaTiO3‐PGMA) nanocomposites were prepared by surface‐initiated atom transfer radical polymerization of GMA from the surface of BaTiO3 nanoparticles. Fourier transform infrared spectroscopy confirmed the grafting of the PGMA shell on the surface of the BaTiO3 nanoparticles cores. Transmission Electron Microscopy results revealed that BaTiO3 nanoparticles are covered by thin brushes (~20 nm) of PGMA forming a core‐shell structure and thermogravimetric analysis results showed that the grafted BaTiO3‐PGMA nanoparticles consist of ~13.7% PGMA by weight. Upon incorporating these grafted nanoparticles into 20 μm‐thick films, the resultant BaTiO3‐PGMA nanocomposites have shown an improved dielectric constant (ε = 54), a high breakdown field strength (~3 MV/cm) and high‐energy storage density ~21.51 J/cm3. AC conductivity measurements were in good agreement with Jonscher's universal power law and low leakage current behavior was observed before the electrical breakdown field of the films. Improved dielectric and electrical properties of core‐shell structured BaTiO3‐PGMA nanocomposite were attributed to good nanoparticle dispersion and enhanced interfacial polarization. Furthermore, only the surface grafted BaTiO3 yielded homogenous films that were mechanically stable. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 719–728 相似文献
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