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Ionic liquid‐based dispersive liquid–liquid microextraction followed by RP‐HPLC determination of saquinavir in rat serum: application to pharmacokinetics 下载免费PDF全文
Nageswara Rao Ramisetti Narendra Varma Nimmu Gangu Naidu Challa 《Biomedical chromatography : BMC》2014,28(12):1874-1880
An ionic liquid‐based dispersive liquid–liquid microextraction followed by RP‐HPLC determination of the most commonly prescribed protease inhibitor, saquinavir, in rat plasma was developed and validated. The effects of different ionic liquids, dispersive solvents, extractant/disperser ratio and salt concentration on sample recovery and enrichment were studied. Among the ionic liquids investigated, 1‐butyl‐3‐methylimidazolium hexafluorophosphate was found to be most effective for extraction of saquinavir from rat serum. The recovery was found to be 95% at an extractant/disperser ratio of 0.43 using 1‐butyl‐3‐methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents. The recovery was further enhanced to 99.5% by addition of 5.0% NaCl. A threefold enhancement in detection and quantification limits was achieved, at 0.01 and 0.03 µg/mL, compared with the conventional protein precipitation method. A linear relationship was observed in the range of 0.035–10.0 µg/mL with a correlation coefficient (r2) of 0.9996. The method was validated and applied to study pharmacokinetics of saquinavir in rat serum. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Varma Nimmu Narendra Naidu Challa Gangu Ramachandra Bondigalla Swamy Arnipalli Manikanta 《Journal of Analytical Chemistry》2021,76(10):1172-1181
Journal of Analytical Chemistry - A water-compatible molecularly imprinted polymer (MIP) was prepared for specific extraction of HIV-1 integrase inhibitor elvitegravir (EVG). It was prepared by a... 相似文献
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Maddila Suresh Gangu Kranthi Kumar Maddila Surya Narayana Jonnalagadda Sreekantha B. 《Research on Chemical Intermediates》2018,44(2):1397-1409
Research on Chemical Intermediates - A facile one-pot green protocol at room temperature has been devised for the synthesis of novel pyrido[2,3-d]-pyrimidine derivatives catalyzed by CeO2-doped... 相似文献
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Sandeep V. H. S. Bhaskaruni Kranthi Kumar Gangu Suresh Maddila Sreekantha B. Jonnalagadda 《Chemical record (New York, N.Y.)》2019,19(9):1793-1812
This personal account mainly introduces and reviews our recent contributions in developing different catalyst materials involving mixed oxides and their scope as renewable catalysts in multicomponent reactions to synthesize various novel heterocyclic scaffolds under green conditions. The application of various mixed oxides and their composites in the organic synthesis is emphasized through this review, in order to reveal the versatility, scope and importance of mixed oxides and their interactions during the reaction. We have also briefed the limitations of mixed oxides as catalysts, to put forward the broader prospective in the field. 相似文献
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Gangu Kranthi Kumar Maddila Suresh Maddila Surya Narayana Jonnalagadda Sreekantha B. 《Research on Chemical Intermediates》2017,43(3):1793-1811
Research on Chemical Intermediates - Novel heterogeneous iron doped fluorapatite (Fe-FAp) catalysts were prepared by co-precipitation in the presence of amino acids, glutamic acid, aspartic acid,... 相似文献
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Maddila Suresh Gangu Kranthi Kumar Maddila Surya Narayana Jonnalagadda Sreekantha B. 《Molecular diversity》2017,21(1):247-255
Molecular Diversity - A simple and versatile one-pot three-component synthetic protocol is devised for heterocycles, viz. 2,6-diamino-4-substituted-4H-pyran-3,5-dicarbonitrile derivatives, in short... 相似文献
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R. Nageswara Rao Hassan Farah Prafulla Kumar Sahu Muthumani Janarthan Ch. Gangu Naidu 《Biomedical chromatography : BMC》2013,27(12):1733-1740
A stability‐indicating reverse‐phase high‐performance liquid chromatography–mass spectrometric method was developed and validated for the assay of metaxalone through forced degradation under acidic, alkaline, photo, oxidative and peroxide stress conditions. Separation of degradation products was accomplished on a reverse‐phase Phenomenex C18 (250 × 4.6 mm, 5 µm) column thermostated at 25°C using 10 mM aqueous ammonium acetate: methanol (35:65 v/v) as mobile phase in an isocratic mode of elution. The eluents were detected at 275 nm by photo diode array detector and mass detectors connected in series. Two unknown base hydrolysis products of metaxalone were identified and characterized as (a) methyl 3‐(3,5‐dimethylphenoxy)‐2‐hydroxypropylcarbamate and (b) 1‐(3,5‐dimethylphenoxy)‐3‐aminopropan‐2‐ol by MS, 1H NMR and FTIR spectroscopy. The method was validated as per International Conference on Harmonization guidelines and metaxalone was selectively determined in presence of its degradation impurities, demonstrating its stability‐indicating nature. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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R. Nageswara Rao Ch. Gangu Naidu K. Guru Prasad Raju Padiya Sachin B. Agwane 《Biomedical chromatography : BMC》2012,26(12):1534-1542
A highly selective, sensitive and rapid hydrophilic liquid interaction chromatographic method was developed and validated for determination of gemifloxacin on dried blood spots. The chromatographic separation was achieved on a reversed‐phase zwitterionic hydrophilic interaction liquid chromatographic ZIC®HILIC‐C18 (4.6 × 100 mm; 5 µm) column using acetonitrile–10 mM ammonium acetate (pH 3.5; 80:20, v/v) as a mobile phase in an isocratic elution mode at a flow rate 0.6 mL/min at 27 °C. An on‐line fluorescence detector set at excitation and emission wavelengths of 269 and 393 nm, respectively was used for monitoring column eluents. Ciprofloxacin was used as an internal standard. The method was validated for accuracy, precision, linearity and selectivity by design of experiments following ICH guidelines. The assay exhibited a linear range of 25–5000 ng/mL for gemifloxacin on dried blood spots. The lower limit of detection was found to be 10 ng/mL. The intra‐ and inter‐assay coefficients of variation did not exceed 7.4% deviation of the nominal concentration. The recovery of GFX from dried blood spots was >95.0% and its stability was excellent with no evidence of degradation during sample processing for at least 3 months storage in a freezer at ?20 °C. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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R. Nageswara Rao Ch. Gangu Naidu K. Guru Prasad R. Narasimha 《Biomedical chromatography : BMC》2011,25(11):1222-1229
A validated stability indicating RP‐HPLC assay of gemifloxacin mesylate was developed by separating its related substances on an Inertsil‐ODS3V‐C18 (4.6 × 250 mm; 5 μm) column using 0.1% trifluoroaceticacid (pH 2.5) and methanol as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min at 27°C. The column effluents were monitored by a photodiode array detector set at 287 nm. The method was validated in terms of accuracy, precision and linearity as per ICH guidelines. Forced degradation of gemifloxacin (GFX) was carried out under acidic, basic, thermal, photolysis and peroxide conditions and the degradation products were separated and characterized by ESI‐MS/MS, 1H and 13C NMR spectroscopy. The method was successfully applied to the analysis of bulk drugs and the recoveries of gemifloxacin and impurities were in the range of 97.60–102.90 and 96.99–102.10%, respectively. No previous reports were found in the literature on identification of degradation products of gemifloxacin. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Sivarami Reddy Gangireddy Venkata Umesh C. Narkhede Vinod D. Jadhav Ch. Gangu Naidu 《Tetrahedron letters》2018,59(17):1670-1673
The first total synthesis was successfully achieved for biologically active 9,10-dihydrophenanthrene-1,5-diol. The key features of our synthetic approach are Perkin condensation, followed by bromination, palladium mediated intramolecular C-C bond coupling, and selective isopropyl ether cleavage. Synthesized compounds were purified and characterized by IR, 1HNMR, 13CNMR and HRMS/LC-MS. 相似文献
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