Navin Sakhare

Bio: Navin Sakhare is an academic researcher from Indian Department of Atomic Energy. The author has contributed to research in topics: Folate receptor & Colloidal gold. The author has an hindex of 2, co-authored 7 publications receiving 13 citations.

Bulk Scale Formulation of Therapeutic Doses of Clinical Grade Ready-to-Use 177Lu-DOTA-TATE: The Intricate Radiochemistry Aspects.

Abstract: Introduction: 177Lu-DOTA-TATE is a clinically useful and promising therapeutic radiopharmaceutical for peptide receptor radionuclide therapy of neuroendocrine tumors (NETs) overexpressing ...

Synthesis and characterization of a novel 99mTc analogue of *I-mIBG showing affinity for nor-epinephrine transport positive tumors

Abstract: Radio-iodine (123I/131I) labeled meta-iodobenzylguanidine (mIBG) is a proven radiopharmaceutical used for diagnosis of neuroendocrine tumors (NET) related to neural crest origin. Here, a 99mTc analogue of *I-mIBG using 99mTc-4+1 labeling approach has been synthesized and evaluated for its potential in NET imaging. This involved preparation of benzylguanidine precursor (mono-dentate donor) which was isolated in a five step synthetic procedure. The precursor was designed such that, in presence of a tetra-dentate NS3 co-ligand, [99mTcO4]− and Sn2+ reducing agent, it formed the desired 99mTc-4+1 complex. Complex formation was identified by radio-HPLC and structural details were affirmed by characterizing its rhenium analogue. Bio-evaluation studies of the complex were carried, both in vitro and in vivo, and the results obtained were compared with no-carrier added-125I-mIBG (nca-125I-mIBG). In vitro studies, in SK-N-SH neuroblastoma cell line showed affinity of the tracer towards nor-epinephrine transporters. Although the absolute uptake was lower compared to nca-125I-mIBG, its specificity was similar (∼90%) as the uptake reduced on inhibition with specific transport blocker, desmethylimipramine (DMI). Biodistribution studies in normal Wistar rats, pre-treated with mIBG and DMI, respectively, showed reduced myocardial uptake than its control. The results thus obtained merits high potential of synthesized 99mTc-4+1 complex for NET imaging.

Synthesis and Biodistribution studies of 99mTc labeled fatty acid derivatives prepared via ‘Click approach’ for potential use in cardiac imaging

Abstract: 123 I-Iodophenylpentadecanoic acid (IPPA) is a metabolic agent used in nuclear medicine for diagnosis of myocardial defects. Efforts are underway worldwide to develop a 99m Tc substitute of the above radiopharmaceutical for the aforementioned application. Herein, we report synthesis and biodistribution studies of 99m Tc labeled fatty acids (8, 11, and 15 carbons) obtained via "click chemistry" for its potential use in myocardial imaging. ω-Bromo fatty acids (8C/11C/15C) were synthetically modified at bromo terminal to introduce a heterocyclic triazole with glycine sidearm in a five step procedure. Modified fatty acids were subsequently radiolabeled with preformed [99m Tc(CO)3 ]+ synthon to yield the desired fatty acid complexes which were evaluated in Swiss mice. All the radiolabeled complexes were obtained with radiochemical purities >80%, as characterized by HPLC. Biodistribution studies of all three complexes in Swiss mice showed myocardial uptake of ~6-9% ID/g at 2 minutes post-injection, close to* I-IPPA (~9% ID/g). Complexes exhibited significant retention in the myocardium up to 30 minutes (~1% ID/g) but were lower to the standard agent (~7% ID/g). Similar uptake of activity in myocardium for the newly synthesized complexes in comparison to 125 I-IPPA along with favorable in vivo pharmacokinetics merits potential for the present "click" design of complexes for myocardial imaging.

Molecular imaging for drug development

Abstract: In vivo molecular imaging has become a key technology for pathophysiological science and drug development. We are mostly utilizing PET(positron emission tomography) as a first-choice modality, because of its ultra-high sensitivity for molecules, adequate temporal and spatial resolution, and especially broad spectrum of target molecules. In vivo molecular imaging could bring the high-quality information about: 1. Molecular diagnosis for living patients with symptoms 2. Closer approach for etiology and differential diagnosis 3. Direct follow-up of key molecules as disease markers 4. Pharmacokinetics/Pharmacodynamics in primates/human 5. Dose finding information for individuals, corresponding to SNPs 6. Direct evidence for accumulation in non-target organs related to adverse effects 7. Drug effects with surrogate markers 8. Early decision of dropout substances (drug candidates) Here, the examples are shown as beta-amyloid imaging for Alzheimer's and mild cognitive impairment, serotonin transporter imaging for chronic fatigue, and dopaminergic components imaging for evaluation of drug for autistic spectrum disorder. In 2005, RIKEN and National Institute of Radiological Science were selected as the key centers for development of All-Japan research network to further promote mutual international and multi -disciplinary collaboration on in vivo molecular imaging.

Chelators and metal complex stability for radiopharmaceutical applications

Abstract: Abstract Diagnostic and therapeutic nuclear medicine relies heavily on radiometal nuclides. The most widely used and well-known radionuclide is technetium-99m (99mTc), which has dominated diagnostic nuclear medicine since the advent of the 99Mo/99mTc generator in the 1960s. Since that time, many more radiometals have been developed and incorporated into potential radiopharmaceuticals. One critical aspect of radiometal-containing radiopharmaceuticals is their stability under in vivo conditions. The chelator that is coordinated to the radiometal is a key factor in determining radiometal complex stability. The chelators that have shown the most promise and are under investigation in the development of diagnostic and therapeutic radiopharmaceuticals over the last 5 years are discussed in this review.