R Nageswara Rao

Summary

Publications

  1. ncbi request reprint Detection of the adulteration of traditional alcoholic beverages by the separation and determination of alprazolam, chloralhydrate and diazepam using reversed-phase high-performance liquid chromatography
    R Nageswara Rao
    HPLC Group, Division of Analytical Chemistry, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
    Anal Sci 20:383-6. 2004
  2. ncbi request reprint Isolation and characterization of process related impurities and degradation products of bicalutamide and development of RP-HPLC method for impurity profile study
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Pharm Biomed Anal 46:505-19. 2008
  3. doi request reprint Enantioselective HPLC resolution of synthetic intermediates of armodafinil and related substances
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Sep Sci 31:981-9. 2008
  4. ncbi request reprint LC-ESI-MS determination and pharmacokinetics of adrafinil in rats
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Chromatogr B Analyt Technol Biomed Life Sci 873:119-23. 2008
  5. doi request reprint Enantioselective separation and determination of adrafinil and modafinil on Chiralcel OJ-H column in rat serum and urine using solid-phase extraction followed by HPLC
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    Biomed Chromatogr 23:811-6. 2009
  6. ncbi request reprint Development and validation of a RP-HPLC method for stability-indicating assay of gemifloxacin mesylate including identification of related substances by LC-ESI-MS/MS, (1) H and (13) C NMR spectroscopy
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, 500 607, India
    Biomed Chromatogr 25:1222-9. 2011
  7. ncbi request reprint Rapid determination of rifaximin on dried blood spots by LC-ESI-MS
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, 500 607, India
    Biomed Chromatogr 25:1201-7. 2011
  8. ncbi request reprint Identification and characterization of stress degradants of lacosamide by LC-MS and ESI-Q-TOF-MS/MS: Development and validation of a stability indicating RP-HPLC method
    Nageswara Rao Ramisetti
    HPLC Group, Analytical Chemistry Division, IICT, Tarnaka, Hyderabad 500007, India Electronic address
    J Pharm Biomed Anal 95:256-64. 2014
  9. ncbi request reprint LC-MS/MS structural characterization of stress degradation products including the development of a stability indicating assay of Darunavir: An anti-HIV drug
    R Nageswara Rao
    Analytical Chemistry Division, D215, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India Electronic address
    J Pharm Biomed Anal 89:28-33. 2014
  10. doi request reprint Development and validation of a stability indicating assay of doxofylline by RP-HPLC: ESI-MS/MS, ¹H and ¹³C NMR spectroscopic characterization of degradation products and process related impurities
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    J Pharm Biomed Anal 78:92-9. 2013

Collaborators

Detail Information

Publications68

  1. ncbi request reprint Detection of the adulteration of traditional alcoholic beverages by the separation and determination of alprazolam, chloralhydrate and diazepam using reversed-phase high-performance liquid chromatography
    R Nageswara Rao
    HPLC Group, Division of Analytical Chemistry, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
    Anal Sci 20:383-6. 2004
    ..8, 4.5 and 0.4 microg, respectively. The validity of the method was checked by analyzing nearly 200 samples collected from different outlets by enforcement authorities, and the extent of adulteration was determined...
  2. ncbi request reprint Isolation and characterization of process related impurities and degradation products of bicalutamide and development of RP-HPLC method for impurity profile study
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Pharm Biomed Anal 46:505-19. 2008
    ..Thus, the developed method can be used for process development as well as quality assurance of bicalutamide in bulk drug and pharmaceutical formulations...
  3. doi request reprint Enantioselective HPLC resolution of synthetic intermediates of armodafinil and related substances
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Sep Sci 31:981-9. 2008
    ..The method was found to be suitable not only for process development of armodafinil but also for determination of the enantiomeric purity of bulk drugs and pharmaceuticals...
  4. ncbi request reprint LC-ESI-MS determination and pharmacokinetics of adrafinil in rats
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Chromatogr B Analyt Technol Biomed Life Sci 873:119-23. 2008
    ..5 ng/ml, which offered high sensitivity for the determination of adrafinil in serum. The method was successfully applied to pharmacokinetic studies of adrafinil after an oral administration to rats...
  5. doi request reprint Enantioselective separation and determination of adrafinil and modafinil on Chiralcel OJ-H column in rat serum and urine using solid-phase extraction followed by HPLC
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    Biomed Chromatogr 23:811-6. 2009
    ..2%). ADL in rat serum was stable over three freeze-thaw cycles at ambient temperature for 4 h. The method was successfully applied to pharmacokinetic studies of adrafinil after an oral administration to rats...
  6. ncbi request reprint Development and validation of a RP-HPLC method for stability-indicating assay of gemifloxacin mesylate including identification of related substances by LC-ESI-MS/MS, (1) H and (13) C NMR spectroscopy
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, 500 607, India
    Biomed Chromatogr 25:1222-9. 2011
    ..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. ..
  7. ncbi request reprint Rapid determination of rifaximin on dried blood spots by LC-ESI-MS
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, 500 607, India
    Biomed Chromatogr 25:1201-7. 2011
    ..5 mL/min. The assay was linear from 0.1 to 10 ng/mL. The mean recovery was 98.42%. The developed method is very simple, rapid and useful for clinical applications. Copyright © 2011 John Wiley & Sons, Ltd. ..
  8. ncbi request reprint Identification and characterization of stress degradants of lacosamide by LC-MS and ESI-Q-TOF-MS/MS: Development and validation of a stability indicating RP-HPLC method
    Nageswara Rao Ramisetti
    HPLC Group, Analytical Chemistry Division, IICT, Tarnaka, Hyderabad 500007, India Electronic address
    J Pharm Biomed Anal 95:256-64. 2014
    ..The developed LC method was validated for the determination of related substances and assay of LAC as per ICH guidelines. This study demonstrates a comprehensive approach of LAC degradation studies during its development phase. ..
  9. ncbi request reprint LC-MS/MS structural characterization of stress degradation products including the development of a stability indicating assay of Darunavir: An anti-HIV drug
    R Nageswara Rao
    Analytical Chemistry Division, D215, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India Electronic address
    J Pharm Biomed Anal 89:28-33. 2014
    ..The proposed structures of degradation products were confirmed by HRMS and the LC method was validated with respect to specificity, linearity, accuracy, recovery, LOD and LOQ. ..
  10. doi request reprint Development and validation of a stability indicating assay of doxofylline by RP-HPLC: ESI-MS/MS, ¹H and ¹³C NMR spectroscopic characterization of degradation products and process related impurities
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    J Pharm Biomed Anal 78:92-9. 2013
    ..The recoveries of doxofylline and impurities were in the range of 99.00-100.05% and 97.83-99.86% respectively...
  11. doi request reprint Liquid chromatographic separation and thermodynamic investigation of stereoisomers of darunavir on Chiralpak AD-H column
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Sep Sci 35:2671-7. 2012
    ....
  12. doi request reprint Determination of gemifloxacin on dried blood spots by hydrophilic interaction liquid chromatography with fluorescence detector: application to pharmacokinetics in rats
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    Biomed Chromatogr 26:1534-42. 2012
    ..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...
  13. doi request reprint RP-HPLC separation and characterization of unknown impurities of a novel HIV-protease inhibitor Darunavir by ESI-MS and 2D NMR spectroscopy
    Ramisetti Nageswara Rao
    D 215, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    J Pharm Biomed Anal 75:186-91. 2013
    ..Two unknown impurities of darunavir were isolated and characterized by ¹H, ¹³C, 2D-NMR and mass spectrometry. The method was validated in terms of accuracy, precision, linearity, robustness, LOD and LOQ...
  14. doi request reprint Liquid chromatography tandem mass spectrometric studies of indinavir sulphate and its forced degradation products
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    J Pharm Biomed Anal 74:101-10. 2013
    ..The proposed structures of degradation products were also confirmed by HRMS studies. No previous reports were found in the literature regarding the characterization of degradation products of indinavir sulphate...
  15. doi request reprint Liquid chromatographic separation of darunavir enantiomers on coated and immobilized amylose tris(3, 5-dimethylphenylcarbamate) chiral stationary phases
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    Chirality 24:652-60. 2012
    ..Van't Hoff plots (ln k' vs. 1/T, ln α vs. 1/T) and apparent thermodynamic parameters were derived to understand the effect of temperature on separation...
  16. doi request reprint LC-ESI-MS/MS determination of paclitaxel on dried blood spots
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    Biomed Chromatogr 26:616-21. 2012
    ..2-20 ng/mL. The limits of detection and quantification were 0.08 and 0.2 ng/mL, respectively. The intra- and inter-day precision (CV%) and accuracy (relative error %) were less than 10 and 12%, respectively...
  17. doi request reprint Evaluation of (R)-(-)-α-methoxy phenyl acetic acid as a chiral shift reagent for resolution and determination of R and S enantiomers of modafinil in bulk drugs and formulations by 1H NMR spectroscopy
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, D215, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    Chirality 24:339-44. 2012
    ..The method was validated and applied successfully to determine the enantiomeric purity of MDL in tablet formulations...
  18. ncbi request reprint On-line 2D-LC-ESI/MS/MS determination of rifaximin in rat serum
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    Biomed Chromatogr 23:1145-50. 2009
    ..The linear dynamic range was 0.5-10 ng/mL (r(2) > 0.998). Acceptable precision and accuracy were obtained over the calibration range. The assay was successfully used in analysis of rat serum to support pharmacokinetic studies...
  19. ncbi request reprint Development of a validated high-throughput LC-ESI-MS method for determination of sirolimus on dried blood spots
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, IICT, Tarnaka, Hyderabad 500007, India
    Biomed Chromatogr 24:1356-64. 2010
    ..The assay was linear from 1 to 100 ng/mL. The mean recovery was 92.42%. The mean inter-day and intra-day precisions were 1.23 and 1.41%, respectively. The developed method is simple, rapid and useful for clinical applications...
  20. doi request reprint Rapid determination of rifaximin in rat serum and urine by direct injection on to a shielded hydrophobic stationary phase by HPLC
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    Biomed Chromatogr 23:563-7. 2009
    ..03 (signal-to-noise ratio >3) and 0.10 microg/mL (signal-to-noise ratio >10), respectively. The method was successfully applied to pharmacokinetic studies of rifaximin after an oral administration to rats...
  21. doi request reprint Separation of stereoisomers of sertraline and its related enantiomeric impurities on a dimethylated beta-cyclodextrin stationary phase by HPLC
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India
    J Pharm Biomed Anal 50:281-6. 2009
    ..The method was validated for determination of enantiomeric purity of sertraline HCl in drug substances and formulations...
  22. doi request reprint Determination of rat plasma levels of sertraline enantiomers using direct injection with achiral-chiral column switching by LC-ESI/MS/MS
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Pharm Biomed Anal 52:398-405. 2010
    ..5-200ng/mL (r(2)>0.999). Acceptable precision and accuracy were obtained over the calibration range. The assay was successfully used in the analysis of SRT enantiomers in rat plasma to support pharmacokinetic studies...
  23. doi request reprint LC-MS/MS studies of ritonavir and its forced degradation products
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Pharm Biomed Anal 53:833-42. 2010
    ..No previous reports were found in the literature regarding the characterization of degradation products of ritonavir...
  24. doi request reprint Separation and characterization of forced degradation products of abacavir sulphate by LC-MS/MS
    R Nageswara Rao
    Analytical Chemistry Division, D215, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Pharm Biomed Anal 54:279-85. 2011
    ..The degradation products were characterized by LC-MS/MS and its fragmentation pathways were proposed. No previous reports were found in the literature regarding the degradation behavior of abacavir sulphate...
  25. doi request reprint Development of a validated LC method for enantiomeric separation and determination of adrafinil and its related substances on a Chiralcel OJ-H column connected to PDA and polarimetric detectors in series
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    Biomed Chromatogr 24:1228-33. 2010
    ..The optical rotation and order of elution of enantiomers were assigned. The method is suitable not only for process development of ADL but also for quality assurance of bulk drugs and pharmaceuticals...
  26. doi request reprint Precolumn derivatization followed by liquid chromatographic separation and determination of tramiprosate in rat plasma by fluorescence detector: application to pharmacokinetics
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory Indian Institute of Chemical Technology IICT, Tarnaka, Hyderabad 500607, India
    J Pharm Biomed Anal 55:282-7. 2011
    ..The method was linear within the range 30.0-1000.0 ng/mL. Design of experiments (DOE) was used to evaluate the robustness of the method. The developed method was applied to study the pharmacokinetics of tramiprosate in rats...
  27. doi request reprint Evaluation of polysaccharide-based chiral stationary phases in quality control of (S)-mirtazapine
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    Biomed Chromatogr 26:142-6. 2012
    ..The elution sequence was determined under the optimized separation conditions...
  28. doi request reprint Enantiomeric separation of mirtazapine and its metabolite in rat plasma by reverse polar ionic liquid chromatography using fluorescence and polarimetric detectors connected in series
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Chromatogr B Analyt Technol Biomed Life Sci 879:1911-6. 2011
    ..The method was linear over the concentration range of 20-5000ng/mL. The method was successfully applied on rat plasma spiked with the enantiomers of mirtazapine and N-desmethyl mirtazapine...
  29. doi request reprint Determination of antibiotics in aquatic environment by solid-phase extraction followed by liquid chromatography-electrospray ionization mass spectrometry
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Chromatogr A 1187:151-64. 2008
    ..The detection and quantification limits were found to be in the range of 0.6-8.1 and 2.0-24.0 microg/L. The surface waters of different lakes and tanks of Hyderabad, India were found to contain a few antibiotics...
  30. doi request reprint Simultaneous separation and determination of coenzyme Q(10) and its process related impurities by NARP-HPLC and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS)
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India
    J Pharm Biomed Anal 47:230-7. 2008
    ..For identification of related substances atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS) was used...
  31. ncbi request reprint Continuous counter current extraction, isolation and determination of solanesol in Nicotiana tobacum L. by non-aqueous reversed phase high performance liquid chromatography
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India
    J Pharm Biomed Anal 46:310-5. 2008
    ..6mm, particle size 5 microm) with isopropyl alcohol-methanol (60:40, v/v) as mobile phase and detection at 215 nm. The product purity was between 95 and 98% (w/w) as determined by HPLC...
  32. ncbi request reprint Development of a validated RP-LC/ESI-MS-MS method for separation, identification and determination of related substances of tamsulosin in bulk drugs and formulations
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 46:94-103. 2008
    ..It finds application not only for monitoring the reactions during the process development but also on quality assurance of tamsulosin...
  33. ncbi request reprint Enantiomeric resolution of doxazosin mesylate and its process-related substances on polysaccharide chiral stationary phases
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 41:766-73. 2006
    ..The method was suitable not only for process development of doxazosin mesylate but also determination of enantiomeric purity of bulk drugs and pharmaceuticals...
  34. ncbi request reprint Use of solid-phase extraction, reverse osmosis and vacuum distillation for recovery of aromatic sulfonic acids from aquatic environment followed by their determination using liquid chromatography-electrospray ionization tandem mass spectrometry
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Chromatogr A 1113:20-31. 2006
    ....
  35. ncbi request reprint Separation, characterization, and quantitation of process-related substances of the anti-hypertensive drug doxazosin mesylate by reversed-phase LC with PDA and ESI-MS as detectors
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 50 0007, India
    J Chromatogr Sci 45:63-9. 2007
    ..The detection limits for the impurities are 0.74 - 4.14 x 10(-9) g, and the method is found to be suitable not only for the monitoring of synthetic reactions, but also for quality assurance of DXZN in bulk drugs and formulations...
  36. ncbi request reprint An overview of the recent developments in analytical methodologies for determination of COX-2 inhibitors in bulk drugs, pharmaceuticals and biological matrices
    R Nageswara Rao
    Analytical Division, Discovery Lab, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 39:349-63. 2005
    ..A critical analysis of the reported data has been carried out and the present state-of-art of the analytical techniques for determination of celecoxib, rofecoxib, etoricoxib, etodolac, nimesulide and meloxicam has been discussed...
  37. ncbi request reprint Development and validation of a reversed-phase HPLC method for monitoring of synthetic reactions during the manufacture of a key intermediate of an anti-hypertensive drug
    Ramisetti Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad, India
    J Sep Sci 29:2303-9. 2006
    ..The method could detect the impurities at a level of 0.01 to 0.20 microg/mL and it was found to be suitable not only for monitoring of reactions but also for quality assurance of 4-amino-2-chloro-6,7-dimethoxyquinazoline...
  38. ncbi request reprint An overview of recent applications of inductively coupled plasma-mass spectrometry (ICP-MS) in determination of inorganic impurities in drugs and pharmaceuticals
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 43:1-13. 2007
    ..The review covers the period from 1995 to 2005 during which the technique was applied not only for determination of metallic impurities but also the assay of various trace elements in pharmaceuticals...
  39. ncbi request reprint Liquid-chromatographic separation and determination of process-related impurities, including a regio-specific isomer of celecoxib on reversed-phase C18 column dynamically coated with hexamethyldisilazane
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
    Anal Sci 22:1257-60. 2006
    ..The method was validated and found to be suitable not only for monitoring the synthetic reactions, but also to evaluate the quality of CXB...
  40. ncbi request reprint Development and validation of a reversed-phase HPLC method for separation and simultaneous determination of process-related substances of mirtazapine in bulk drugs and formulations
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Tarnaka, Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Chromatogr Sci 47:223-30. 2009
    ..38-100.73% with < 0.52% RSD. The method is useful not only for rapid evaluation of the purity of mirtazapine, but also for the simultaneous determination of related substances in bulk drugs and pharmaceutical formulations...
  41. ncbi request reprint Development and validation of a reversed-phase liquid chromatographic method for separation and simultaneous determination of COX-2 inhibitors in pharmaceuticals and its application to biological fluids
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 50 0007, India
    Biomed Chromatogr 19:362-8. 2005
    ..It is simple, rapid, selective and capable of detecting and determining COX-2 inhibitors with a detection limit of 0.127--1.040 microg/mL simultaneously...
  42. doi request reprint Reversed-phase liquid chromatographic determination of tramiprosate in rat plasma using evaporative light scattering detector
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    Biomed Chromatogr 25:925-9. 2011
    ..58 to 5.96%, and the CV for a quality control sample at 10 µg/mL was 5.96% with a bias of -7.50% from the target value. The method described here is suitable for management of tramiprosate in Alzheimer disease therapy...
  43. ncbi request reprint Rapid separation and determination of process-related substances of paracetamol using reversed-phase HPLC with photo diode array as a detector
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500 007, India
    Anal Sci 22:287-92. 2006
    ..The method could be of use not only for rapid and routine evaluation of the quality of paracetamol in bulk drug manufacturing units but also for detection of its impurities in pharmaceutical formulations...
  44. doi request reprint Development of a validated LC-MS/MS method for determination of doxofylline on rat dried blood spots and urine: application to pharmacokinetics
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Tarnaka, Hyderabad 500 607, India Electronic address
    J Pharm Biomed Anal 78:211-6. 2013
    ..24 and 0.84 ng/mL in DBS and 0.28 and 1.00 ng/mL in urine samples respectively. The method was validated as per ICH guidelines and successfully applied to a pharmacokinetic study of doxofylline in rats...
  45. doi request reprint Development of a molecularly imprinted polymer for selective extraction followed by liquid chromatographic determination of sitagliptin in rat plasma and urine
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology IICT, Tarnaka, Hyderabad 500607, India
    Talanta 85:950-7. 2011
    ..03 and 0.10 μg/L respectively. The proposed method overcomes the matrix effects of phospholipids generally encountered while preparation of plasma samples by precipitation of proteins...
  46. ncbi request reprint Development of a validated liquid chromatographic method for determination of related substances of telmisartan in bulk drugs and formulations
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Pharm Biomed Anal 56:471-8. 2011
    ..The related substances relate to a novel synthetic route and different from those A-H impurities reported by European Pharmacopeia...
  47. ncbi request reprint Development and validation of a liquid chromatographic method for determination of enantiomeric purity of citalopram in bulk drugs and pharmaceuticals
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Pharm Biomed Anal 41:280-5. 2006
    ..63% (%R.S.D.) and recoveries were in the range 99.38-100.41%. The method was validated and found to be suitable for determination enantiomeric purity of citalopram in bulk drugs and pharmaceutical formulations...
  48. doi request reprint Isolation and characterization of a potential process related impurity of phenazopyridine HCl by preparative HPLC followed by MS-MS and 2D-NMR spectroscopy
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Pharm Biomed Anal 49:1287-91. 2009
    ..The formation of the impurity was discussed. To our knowledge, it is a novel impurity not reported elsewhere...
  49. ncbi request reprint An improved and validated LC method for resolution of bicalutamide enantiomers using amylose tris-(3,5-dimethylphenylcarbamate) as a chiral stationary phase
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Pharm Biomed Anal 42:347-53. 2006
    ..4, 3.0 and 7.6, 9.3) x 10(-8)g/ml for (S)-(+)-BCT and (R)-(-)-BCT enantiomers, respectively. The method was found to be suitable for rapid determination of enantiomeric purity of bicalutamide in bulk drugs and pharmaceutical formulations...
  50. ncbi request reprint Enantiospecific assay of citadiol--a key intermediate of escitalopram by liquid chromatography on Chiralpak AD-H column connected with UV and polarimetric detectors in series
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Pharm Biomed Anal 43:311-4. 2007
    ..1-300 microg/ml for R-CTD and S-CTD, respectively and the r2 was > or = 0.9999. The inter- and intra-day assay precision was less than 0.74% (%R.S.D.) and the recoveries were in the range 99.68-100.72% with %R.S.D. < 0.49%...
  51. doi request reprint Liquid chromatography-mass spectrometric determination of losartan and its active metabolite on dried blood spots
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
    J Chromatogr B Analyt Technol Biomed Life Sci 902:47-54. 2012
    ..Additional validation parameters such as influence of hematocrit and spot volume were also evaluated and found to be well within the acceptable limits...
  52. ncbi request reprint Separation and determination of synthetic impurities of difloxacin by reversed-phase high-performance liquid chromatography
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 36:729-35. 2004
    ..The method was found to be specific, precise and reliable for the determination of unreacted levels of raw materials, intermediates in the reaction mixtures and the finished products of difloxacin...
  53. ncbi request reprint Preparative isolation and characterization of some minor impurities of astaxanthin by high-performance liquid chromatography
    R Nageswara Rao
    Indian Institute of Chemical Technology, Hyderabad 500007, India
    J Chromatogr A 1076:189-92. 2005
    ..The impurities collected using the developed conditions were over 98% pure...
  54. doi request reprint Ionic-liquid based dispersive liquid-liquid microextraction followed by high performance liquid chromatographic determination of anti-hypertensives in rat serum
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
    J Chromatogr B Analyt Technol Biomed Life Sci 931:174-80. 2013
    ..50%. The relative standard deviations of intra-and inter-day accuracy varied between 1.9 and 9.1% (n=3). The linearity of the proposed method was 0.1-20μg/mL with coefficients of determination varying between 0.9979 and 0.9992. ..
  55. ncbi request reprint Development and validation of a liquid chromatographic method for determination of related-substances of mosapride citrate in bulk drugs and pharmaceuticals
    R Nageswara Rao
    HPLC UV Group, Division of Analytical Chemistry, Discovery Laboratory Indian Institute of Chemical Technology, Hyderabad 50 0007, India
    J Pharm Biomed Anal 36:759-67. 2004
    ..53 to 100.7. The method was found to be suitable not only for monitoring the reactions during the process development but also quality assurance of mosapride citrate...
  56. ncbi request reprint Enantioselective determination of a gastroprokinetic drug using amylose tris-(3,5-dimethylphenylcarbamate) as a stationary phase by HPLC
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, Andhra Pradesh, India
    J Pharm Biomed Anal 40:338-44. 2006
    ..9997. The recoveries were in the range 99.63-100.22%, the method was suitable not only for process development of mosapride citrate but also for quality assurance of the individual enantiomers in bulk drugs and pharmaceuticals...
  57. doi request reprint LC-MS/MS determination of pramipexole on rat dried blood spots: a pharmacokinetic study
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500607, India
    J Chromatogr B Analyt Technol Biomed Life Sci 932:34-9. 2013
    ..Influence of hematocrit and spot volume on dried blood spot was also evaluated and found to be well within the acceptable limits. The method was successfully applied to pharmacokinetic studies of PRX in rats. ..
  58. ncbi request reprint Development and substantiation of a liquid chromatographic method for monitoring organic reactions involved in synthesis of 4-methoxyphenylacetic acid
    R Nageswara Rao
    Division of Analytical Chemistry, Indian Institute of Chemical Technology, Tarnaka, Hyderabad
    J Chromatogr A 972:277-82. 2002
    ..The method was found to be suitable not only for monitoring the reactions but also for quality assurance of PMPA as it could detect impurities at the level of 4 x 10(-9) g...
  59. ncbi request reprint Differentiation of diastereomeric N-aryltetrahydropyrano/tetrahydrofuranochromenylamines under electron ionization and chemical ionization conditions
    G S Ramanjaneyulu
    National Centre for Mass Spectrometry, Indian Institute of Chemical Technology, Hyderabad 500 007, India
    Rapid Commun Mass Spectrom 21:3511-9. 2007
    ..The results of theoretical calculations performed are in accordance with the experimental observations. The CI experiments (methane and isobutane) on all the diastereomeric compounds also enabled the differentiation of the isomers...
  60. ncbi request reprint Simultaneous separation and determination of process-related substances and degradation products of venlafaxine by reversed-phase HPLC
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Hyderabad, India
    J Sep Sci 29:2733-44. 2006
    ..Forced degradation of venlafaxine was carried out under thermal, photo, acidic, basic and peroxide conditions and the acid degradation products were characterized by ESI-MS/MS, 1H NMR and FT-IR spectral data...
  61. ncbi request reprint An overview of the recent trends in development of HPLC methods for determination of impurities in drugs
    R Nageswara Rao
    HPLC Group, Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 33:335-77. 2003
    ....
  62. ncbi request reprint High-performance liquid chromatographic determination of anti- hypertensive drugs on dried blood spots using a fluorescence detector - method development and validation
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology IICT, Tarnaka, Hyderabad, 500607, India
    Biomed Chromatogr 25:1252-9. 2011
    ..07 and 1.34%, 1.42 and 1.48%, and 3.20 and 2.15% respectively. The proposed method was simple and rapid. Design of experiments was used to evaluate the robustness of the method. Copyright © 2011 John Wiley & Sons, Ltd. ..
  63. doi request reprint Development and validation of a stability-indicating assay including the isolation and characterization of degradation products of metaxalone by LC-MS
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad, 500 007, India
    Biomed Chromatogr 27:1733-40. 2013
    ..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...
  64. ncbi request reprint Changes in behavior and brain acetylcholinesterase activity in mosquito fish, Gambusia affinis in response to the sub-lethal exposure to chlorpyrifos
    J Venkateswara Rao
    Toxicology Unit, Biology Division, Indian Institute of Chemical Technology, Hyderabad, India
    Int J Environ Res Public Health 2:478-83. 2005
    ..affinis in relation to the length of exposure. The findings revealed that the locomotor activity of test organism could be considered as a suitable marker to evaluate the affect of toxicant even at LOEC levels...
  65. doi request reprint Synthesis, structure-activity relationship of novel substituted 4H-chromen-1,2,3,4-tetrahydropyrimidine-5-carboxylates as potential anti-mycobacterial and anticancer agents
    B China Raju
    Organic Chemistry Division 1, Indian Institute of Chemical Technology, Hyderabad 500 607, India
    Bioorg Med Chem Lett 21:2855-9. 2011
    ..This is the first report assigning in vitro anti-mycobacterial, anticancer and structure-activity relationship for this new class of 4H-chromen-1,2,3,4-tetrahydropyrimidine-5-carboxylates...
  66. ncbi request reprint Development and validation of a liquid chromatographic method for monitoring of process-related synthetic organic impurities of profenofos in technical products
    R Nageswara Rao
    HPLC UV Group, Analytical Chemistry Division, Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500 007, India
    J Chromatogr Sci 41:418-21. 2003
    ..The method is found to be suitable not only for monitoring the reactions involved in the process development of PFS, but also quality assurance, as it can detect impurities at the level of 1.5 x 10(-8) g...
  67. ncbi request reprint Separation and determination of synthetic impurities of norfloxacin by reversed-phase high performance liquid chromatography
    R Nageswara Rao
    Analytical Chemistry Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
    J Pharm Biomed Anal 34:1049-56. 2004
    ..It was found to be specific, precise and reliable for determination of unreacted levels of raw materials, intermediates and the finished products of norfloxacin...
  68. doi request reprint Two-dimensional LC-MS/MS determination of antiretroviral drugs in rat serum and urine
    R Nageswara Rao
    Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 007, India
    J Pharm Biomed Anal 50:994-9. 2009
    ..7 ng ml(-1). The calibration graphs were linear in the range of 4-50 ng ml(-1)for abacavir, nevirapine and indinavir. The method was successfully applied to study the pharmacokinetics of antiretroviral in rats...