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Papers by sankha chattopadhyay
PubMed, 2005
Nicotine alpha(4)beta(2) receptor subtypes are implicated in the study of Alzheimer's disease, sc... more Nicotine alpha(4)beta(2) receptor subtypes are implicated in the study of Alzheimer's disease, schizophrenia, substance abuse, lung cancer, and other disorders. We report the development and evaluation of a putative antagonist, 5-(3'-fluoropropyl)-3-(2-(S)-pyrrolidinylmethoxy)pyridine (nifrolidine) as a PET agent for nicotine alpha(4)beta(2) receptors. Methods: In vitro binding affinity of nifrolidine was measured in rat brain slices labeled with (125)I-iodoepibatidine or (125)I-bungaratoxin. Selectivity of binding was measured in the presence of cytisine. (18)F radiolabeling was performed by reacting the tosylate precursor with (18)F-fluoride followed by deprotection. In vitro autoradiographic studies in rat brain slices with 5-(3'-(18)F-fluoropropyl)-3-(2-(S)-pyrrolidinylmethoxy)pyridine ((18)F-nifrolidine) were read on a phosphor imager. Rats were injected with (18)F-nifrolidine (3.7 MBq each), and brain regions were counted at various times (2-120 min). Blocking studies were performed by subcutaneous injection of nicotine (10 mg/kg). A PET study of (18)F-nifrolidine (approximately 148 MBq) was performed on an anesthetized rhesus monkey using a high-resolution scanner. Results: In vitro binding affinity of nifrolidine exhibited an inhibition constant of 2.89 nmol/L for the alpha(4)beta(2) sites. Radiosynthesis and high-performance liquid chromatography purifications yielded the product in approximately 20%-40% decay-corrected radiochemical yield to provide (18)F-nifrolidine specific activities of approximately 111-185 GBq/mumol. In vitro autoradiography in rat brain slices revealed selective binding of (18)F-nifrolidine to the anteroventral thalamic nucleus, ventral posteriomedial thalamus, dorsolateral geniculate, and, to a lesser extent, cortex and striata, which are known to contain alpha(4)beta(2) sites. This specific binding was completely abolished by 300 mumol/L nicotine. Ex vivo rat brain distribution studies indicated selective binding in the thalamus with a maximal thalamus-to-cerebellum ratio of approximately 3. The PET study revealed selective maximal uptake (0.01% injected dose/mL) in regions of the thalamus (anteroventral and anteromedial thalamus, ventrolateral thalamus) and extrathalamic regions such as cingulate gyrus, lateral geniculate, temporal cortex, and frontal cortex. Conclusion: Binding of (18)F-nifrolidine to alpha(4)beta(2) receptor-rich regions in rats and monkeys indicates promise as a PET agent. Additionally, the thalamus-to-cerebellum ratio approached a plateau of 1.7 in 120 min, indicating relatively faster kinetics compared with previously reported imaging agents.
Applied Radiation and Isotopes
BioMed Research International, 2014
Journal of Radioanalytical and Nuclear Chemistry, 2019
The aim of this work was to develop a method for purification of the spent 100/99Mo–99mTc generat... more The aim of this work was to develop a method for purification of the spent 100/99Mo–99mTc generator free from non-isotopic impurities like Nb, Y, Zr and recovery of 99mTc using a Sephadex column and MEK solvent extraction technique, respectively. This study was done by performing simulation experiment with 98Mo(n,γ)99Mo solution doped with the radiotracers of the above said non-isotopic impurities. There was respective adsorption of non-isotopic impurities of Nb, Zr and Y on Sephadex column (99.99%; n = 3) and extraction 99mTc in MEK. The extraction efficiency of pure 99mTc (radionuclidic purity: 99.99%, n = 3) from various Mo solution was 97% (n = 3).
Biomaterials Science, 2019
Somatostatin receptor (SSTR) analog modified nanoparticles of paclitaxel (PSM) showed a superior ... more Somatostatin receptor (SSTR) analog modified nanoparticles of paclitaxel (PSM) showed a superior anti-melanoma effect by inducing a favorable systemic immune response.
Journal of Radioanalytical and Nuclear Chemistry, 2017
Zirconium-89 (89Zr) is an interesting immuno-PET imaging agent due to its favorable physical char... more Zirconium-89 (89Zr) is an interesting immuno-PET imaging agent due to its favorable physical characteristics of 78.4 h half-life and a relatively low positron energy of 0.9 MeV. Radiochemical separation of 89Zr from irradiated yttrium target matrix has been achieved by different separation methodologies like anion-exchange chromatography, cation-exchange chromatography and size exclusion chromatography (Sephadex G-25 resin). A novel and simple method based on size exclusion chromatography (Sephadex G-25) for radiochemical separation of 89Zr with no harmful substances has been explored. The experimental yield of 89Zr from natural yttrium target was found to be 27 MBq/μAh using 12 MeV proton. The radiochemical separation yield, radionuclidic purity and chemical purity of 89Zr using an anion exchanger, Dowex-1 resin/2 M HCl column system and Sephadex G-25 resin column was found to be high enough.
Journal of labelled compounds & radiopharmaceuticals, 2016
Gallium-68 radioisotope is an excellent source in clinical positron emission tomography applicati... more Gallium-68 radioisotope is an excellent source in clinical positron emission tomography application due to its ease of availability from germanium-68 ((68) Ge)/gallium-68 ((68) Ga) generator having a shelf life of 1 year. In this paper, a modified method for purification of the primary eluate of (68) Ge-(68) Ga generator by using a small cation exchange resin (Dowex-50) column has been described. The breakthrough of (68) Ge before and after purification of (68) Ga eluate was 0.014% and 0.00027%, respectively. The average recovery yield of (68) Ga after purification was 84% ± 8.6% (SD, n = 335). The results of the physiochemical studies confirmed that the (68) Ga-acetate obtained is suitable for labeling of radiopharmaceuticals.
Journal of Nanoparticle Research, 2016
BioMed research international, 2014
The objective of the present study was to develop bilayer tablets of atorvastatin and atenolol th... more The objective of the present study was to develop bilayer tablets of atorvastatin and atenolol that are characterized by initial fast-release of atorvastatin in the stomach and comply with the release requirements of sustained-release of atenolol. An amorphous, solvent evaporation inclusion complex of atorvastatin with β -cyclodextrin, present in 1 : 3 (drug/cyclodextrin) molar ratio, was employed in the fast-release layer to enhance the dissolution of atorvastatin. Xanthan gum and guar gum were integrated in the sustained-release layer. Bilayer tablets composed of sustained-release layer (10% w/w of xanthan gum and guar gum) and fast-release layer [1 : 3 (drug/cyclodextrin)] showed the desired release profile. The atorvastatin contained in the fast-release layer showed an initial fast-release of more than 60% of its drug content within 2 h, followed by sustained release of the atenolol for a period of 12 h. The pharmacokinetic study illustrated that the fast absorption and increase...
Journal of Radioanalytical and Nuclear Chemistry, 2014
ABSTRACT
International Journal of Biological Macromolecules, 2014
The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of ... more The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of floating matrix tablet of atenolol using polymer blend derived from Xanthomonas campesteris and Cyamopsis tetragonolobus that are characterized by release requirements of sustained-release product and to improve the oral bioavailability of the drug. A 3(2) full factorial design was employed to optimize the tablets, where content of polymer blend (X1) and ratio of xanthan gum-to-guar gum (X2) were considered as independent variables. The effects of independent variables on dependent variables, i.e. floating time, diffusion exponent, and time to release 50% of atenolol were evaluated. The in vivo pharmacokinetic parameters of the optimized formulation were compared with the marketed sustained release formulation of atenolol (Aten(®)). The optimized formulation containing 20% (w/w) of polymer blend and 50:50 ratio of xanthan gum-to-guar gum was able to float more than 12h and showed the desired sustained drug release from the tablets. In vivo retention studies in rabbit stomach showed the gastric residence of tablet up to 6h. The in vivo study of optimized tablets illustrated significant improvement in the oral bioavailability of atenolol in rabbits. It can be concluded that floating matrix tablet of atenolol prepared by using xanthan gum and guar gum has potential for sustained release of the drug as well as improved oral bioavailability through enhanced gastric residence time of formulation in stomach.
Applied Radiation and Isotopes, 1997
The Journal of Nuclear Medicine, 2009
![Research paper thumbnail of Clinical Efficacy of Sodium [99mTc] Pertechnetate from Low Specific Activity 99Mo/99mTc Autosolex Generator in Hospital Radiopharmacy Centre](https://attachments.academia-assets.com/79614298/thumbnails/1.jpg)
](Nuclear medicine review. Central & Eastern Europe, 2020
BACKGROUND Few nuclear reactors in the world producing high specific activity (HSA) 99Mo using en... more BACKGROUND Few nuclear reactors in the world producing high specific activity (HSA) 99Mo using enriched 235U (HEU), are aging and are planned for shut down in the near future. Further, HEU will not be freely available, due to safeguards, and the technology for 99Mo from low-enriched 235U (LEU) is not yet widely accepted since 239Pu contamination in the product is an issue. Production of 99mTc from low specific activity (LSA) 99Mo obtained from 98Mo(n,)99Mo reaction in research reactor and 100Mo(,n)99Mo reaction in accelerator or directly from 100Mo(p,2n)99mTc nuclear reaction in cyclotron, has been explored [1]. The methyl ethyl ketone (MEK) based solvent extraction technique is n well known method for the separation of 99mTc from low specific activity 99Mo. The 99Mo/99mTc autosolex generator [2], a computer controlled automated module, utilizes the conventional MEK solvent extraction method for extraction of 99mTc. Herein, we have validated the usage of autosolex for preparation ...
The Journal of Nuclear Medicine, 2008
Applied Radiation and Isotopes
PubMed, 2005
Nicotine alpha(4)beta(2) receptor subtypes are implicated in the study of Alzheimer's disease, sc... more Nicotine alpha(4)beta(2) receptor subtypes are implicated in the study of Alzheimer's disease, schizophrenia, substance abuse, lung cancer, and other disorders. We report the development and evaluation of a putative antagonist, 5-(3'-fluoropropyl)-3-(2-(S)-pyrrolidinylmethoxy)pyridine (nifrolidine) as a PET agent for nicotine alpha(4)beta(2) receptors. Methods: In vitro binding affinity of nifrolidine was measured in rat brain slices labeled with (125)I-iodoepibatidine or (125)I-bungaratoxin. Selectivity of binding was measured in the presence of cytisine. (18)F radiolabeling was performed by reacting the tosylate precursor with (18)F-fluoride followed by deprotection. In vitro autoradiographic studies in rat brain slices with 5-(3'-(18)F-fluoropropyl)-3-(2-(S)-pyrrolidinylmethoxy)pyridine ((18)F-nifrolidine) were read on a phosphor imager. Rats were injected with (18)F-nifrolidine (3.7 MBq each), and brain regions were counted at various times (2-120 min). Blocking studies were performed by subcutaneous injection of nicotine (10 mg/kg). A PET study of (18)F-nifrolidine (approximately 148 MBq) was performed on an anesthetized rhesus monkey using a high-resolution scanner. Results: In vitro binding affinity of nifrolidine exhibited an inhibition constant of 2.89 nmol/L for the alpha(4)beta(2) sites. Radiosynthesis and high-performance liquid chromatography purifications yielded the product in approximately 20%-40% decay-corrected radiochemical yield to provide (18)F-nifrolidine specific activities of approximately 111-185 GBq/mumol. In vitro autoradiography in rat brain slices revealed selective binding of (18)F-nifrolidine to the anteroventral thalamic nucleus, ventral posteriomedial thalamus, dorsolateral geniculate, and, to a lesser extent, cortex and striata, which are known to contain alpha(4)beta(2) sites. This specific binding was completely abolished by 300 mumol/L nicotine. Ex vivo rat brain distribution studies indicated selective binding in the thalamus with a maximal thalamus-to-cerebellum ratio of approximately 3. The PET study revealed selective maximal uptake (0.01% injected dose/mL) in regions of the thalamus (anteroventral and anteromedial thalamus, ventrolateral thalamus) and extrathalamic regions such as cingulate gyrus, lateral geniculate, temporal cortex, and frontal cortex. Conclusion: Binding of (18)F-nifrolidine to alpha(4)beta(2) receptor-rich regions in rats and monkeys indicates promise as a PET agent. Additionally, the thalamus-to-cerebellum ratio approached a plateau of 1.7 in 120 min, indicating relatively faster kinetics compared with previously reported imaging agents.
Applied Radiation and Isotopes
BioMed Research International, 2014
Journal of Radioanalytical and Nuclear Chemistry, 2019
The aim of this work was to develop a method for purification of the spent 100/99Mo–99mTc generat... more The aim of this work was to develop a method for purification of the spent 100/99Mo–99mTc generator free from non-isotopic impurities like Nb, Y, Zr and recovery of 99mTc using a Sephadex column and MEK solvent extraction technique, respectively. This study was done by performing simulation experiment with 98Mo(n,γ)99Mo solution doped with the radiotracers of the above said non-isotopic impurities. There was respective adsorption of non-isotopic impurities of Nb, Zr and Y on Sephadex column (99.99%; n = 3) and extraction 99mTc in MEK. The extraction efficiency of pure 99mTc (radionuclidic purity: 99.99%, n = 3) from various Mo solution was 97% (n = 3).
Biomaterials Science, 2019
Somatostatin receptor (SSTR) analog modified nanoparticles of paclitaxel (PSM) showed a superior ... more Somatostatin receptor (SSTR) analog modified nanoparticles of paclitaxel (PSM) showed a superior anti-melanoma effect by inducing a favorable systemic immune response.
Journal of Radioanalytical and Nuclear Chemistry, 2017
Zirconium-89 (89Zr) is an interesting immuno-PET imaging agent due to its favorable physical char... more Zirconium-89 (89Zr) is an interesting immuno-PET imaging agent due to its favorable physical characteristics of 78.4 h half-life and a relatively low positron energy of 0.9 MeV. Radiochemical separation of 89Zr from irradiated yttrium target matrix has been achieved by different separation methodologies like anion-exchange chromatography, cation-exchange chromatography and size exclusion chromatography (Sephadex G-25 resin). A novel and simple method based on size exclusion chromatography (Sephadex G-25) for radiochemical separation of 89Zr with no harmful substances has been explored. The experimental yield of 89Zr from natural yttrium target was found to be 27 MBq/μAh using 12 MeV proton. The radiochemical separation yield, radionuclidic purity and chemical purity of 89Zr using an anion exchanger, Dowex-1 resin/2 M HCl column system and Sephadex G-25 resin column was found to be high enough.
Journal of labelled compounds & radiopharmaceuticals, 2016
Gallium-68 radioisotope is an excellent source in clinical positron emission tomography applicati... more Gallium-68 radioisotope is an excellent source in clinical positron emission tomography application due to its ease of availability from germanium-68 ((68) Ge)/gallium-68 ((68) Ga) generator having a shelf life of 1 year. In this paper, a modified method for purification of the primary eluate of (68) Ge-(68) Ga generator by using a small cation exchange resin (Dowex-50) column has been described. The breakthrough of (68) Ge before and after purification of (68) Ga eluate was 0.014% and 0.00027%, respectively. The average recovery yield of (68) Ga after purification was 84% ± 8.6% (SD, n = 335). The results of the physiochemical studies confirmed that the (68) Ga-acetate obtained is suitable for labeling of radiopharmaceuticals.
Journal of Nanoparticle Research, 2016
BioMed research international, 2014
The objective of the present study was to develop bilayer tablets of atorvastatin and atenolol th... more The objective of the present study was to develop bilayer tablets of atorvastatin and atenolol that are characterized by initial fast-release of atorvastatin in the stomach and comply with the release requirements of sustained-release of atenolol. An amorphous, solvent evaporation inclusion complex of atorvastatin with β -cyclodextrin, present in 1 : 3 (drug/cyclodextrin) molar ratio, was employed in the fast-release layer to enhance the dissolution of atorvastatin. Xanthan gum and guar gum were integrated in the sustained-release layer. Bilayer tablets composed of sustained-release layer (10% w/w of xanthan gum and guar gum) and fast-release layer [1 : 3 (drug/cyclodextrin)] showed the desired release profile. The atorvastatin contained in the fast-release layer showed an initial fast-release of more than 60% of its drug content within 2 h, followed by sustained release of the atenolol for a period of 12 h. The pharmacokinetic study illustrated that the fast absorption and increase...
Journal of Radioanalytical and Nuclear Chemistry, 2014
ABSTRACT
International Journal of Biological Macromolecules, 2014
The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of ... more The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of floating matrix tablet of atenolol using polymer blend derived from Xanthomonas campesteris and Cyamopsis tetragonolobus that are characterized by release requirements of sustained-release product and to improve the oral bioavailability of the drug. A 3(2) full factorial design was employed to optimize the tablets, where content of polymer blend (X1) and ratio of xanthan gum-to-guar gum (X2) were considered as independent variables. The effects of independent variables on dependent variables, i.e. floating time, diffusion exponent, and time to release 50% of atenolol were evaluated. The in vivo pharmacokinetic parameters of the optimized formulation were compared with the marketed sustained release formulation of atenolol (Aten(®)). The optimized formulation containing 20% (w/w) of polymer blend and 50:50 ratio of xanthan gum-to-guar gum was able to float more than 12h and showed the desired sustained drug release from the tablets. In vivo retention studies in rabbit stomach showed the gastric residence of tablet up to 6h. The in vivo study of optimized tablets illustrated significant improvement in the oral bioavailability of atenolol in rabbits. It can be concluded that floating matrix tablet of atenolol prepared by using xanthan gum and guar gum has potential for sustained release of the drug as well as improved oral bioavailability through enhanced gastric residence time of formulation in stomach.
Applied Radiation and Isotopes, 1997
The Journal of Nuclear Medicine, 2009
Nuclear medicine review. Central & Eastern Europe, 2020
BACKGROUND Few nuclear reactors in the world producing high specific activity (HSA) 99Mo using en... more BACKGROUND Few nuclear reactors in the world producing high specific activity (HSA) 99Mo using enriched 235U (HEU), are aging and are planned for shut down in the near future. Further, HEU will not be freely available, due to safeguards, and the technology for 99Mo from low-enriched 235U (LEU) is not yet widely accepted since 239Pu contamination in the product is an issue. Production of 99mTc from low specific activity (LSA) 99Mo obtained from 98Mo(n,)99Mo reaction in research reactor and 100Mo(,n)99Mo reaction in accelerator or directly from 100Mo(p,2n)99mTc nuclear reaction in cyclotron, has been explored [1]. The methyl ethyl ketone (MEK) based solvent extraction technique is n well known method for the separation of 99mTc from low specific activity 99Mo. The 99Mo/99mTc autosolex generator [2], a computer controlled automated module, utilizes the conventional MEK solvent extraction method for extraction of 99mTc. Herein, we have validated the usage of autosolex for preparation ...
The Journal of Nuclear Medicine, 2008
Applied Radiation and Isotopes
Updates on the PET and SPECT Radiopharmaceuticals production in 30MeV Cyclotron, MCF, BRIT, Ko... more Updates on the PET and SPECT Radiopharmaceuticals production in 30MeV Cyclotron, MCF, BRIT, Kolkata , DAE