Radiolabeling with technetium-99m to study high-capacity and low-capacity biochemical systems

Abstract

After a brief review of the history of the development of technetium-99m-labeled radiopharmaceuticals, the use of technetium chelates in high-capacity systems is discussed. The latter are used in the study of five organ systems, the kidneys, liver, bone, brain, and heart. The chemical characterization of 99mTc complexes is also reviewed, followed by discussion of the various approaches to the labeling of proteins with direct labeling, the preformed chelate approach, and the antibody chelator conjugate approach. Thereafter, the labeling of biochemicals with 99mTc for use with easily saturated sites, e.g., receptors and enzymes, is considered. Finally, attention is given to factors that affect the preparation of high specific activity, high affinity 99mTc-labeled biochemicals.

Evaluation of brain targeting efficiency of intranasal microemulsion containing olanzapine: pharmacodynamic and pharmacokinetic consideration

“…Drug in OZPS and the formulations, OZPME and OZPMME, were radiolabeled using technetium-99 ( 99m Tc) by direct labeling method (Eckelman, 1995;Babbar et al, 2000;Li et al, 2002;Zhang et al, 2004;Vyas et al, 2006b;Kaur & Kim, 2008;Patel et al, 2013b). To 1.0 mL of OZP formulation, 200 mL of stannous chloride dehydrate (2 mg/mL in 10% acetic acid) was added, the pH was adjusted to 6.0-6.5 using 50 mM sodium bicarbonate solution.…”

“…The radiochemical purity (Eckelman, 1995;Babbar et al, 2000;Patel et al, 2013b) of 99m Tc-labeled OZPS ( 99m Tc-OZPS), 99m Tc-labeled OZPME ( 99m Tc-OZPME) and 99m Tc-labeled OZPMME ( 99m Tc-OZPMME) was determined by ascending instant TLC using silica gel-coated fiberglass sheets and acetone as the mobile phase. The effects of incubation time, pH and stannous chloride concentration on radiolabeling efficiency were studied to achieve optimum conditions.…”

“…The effects of incubation time, pH and stannous chloride concentration on radiolabeling efficiency were studied to achieve optimum conditions. The radiolabeled formulations were challenged to assess bonding strength at different molar concentrations (25-100 mM) of diethylene triamine penta acetic acid (Eckelman, 1995;Babbar et al, 2000;Patel et al, 2013b). The optimized radiolabeled-drug formulations were evaluated for in vitro stability in 0.90% (w/v) sodium chloride (normal saline) and in plasma (Eckelman, 1995;Babbar et al, 2000;Patel et al, 2013b).…”

Paliperidone microemulsion for nose-to-brain targeted drug delivery system: pharmacodynamic and pharmacokinetic evaluation

“…The effects of incubation time, pH and stannous chloride concentration on radiolabeling efficiency were studied to achieve optimum conditions. All 99m Tc-tagged formulations were challenged to assess bonding strength at different molar concentrations (25-100 mM) of diethylene triamine penta acetic acid (Eckelman, 1995;Babbar et al, 2000;Patel et al, 2013b). The optimized 99m Tc-tagged formulations were evaluated for in vitro stability in 0.90% (w/v) sodium chloride (normal saline) and in plasma (Eckelman, 1995;Babbar et al, 2000;Patel et al, 2013b).…”

“…PALI in PALI-SOL, PALI-ME and PALI-MME, was tagged with radioactive substance, technetium-99 ( 99m Tc) by the direct labeling method (Eckelman, 1995;Babbar et al, 2000;Li et al, 2002;Zhang et al 2004;Vyas et al 2006;Kaur & Kim, 2008;Patel et al 2013b). To 1.0 mL of PALI formulation, 200 mL of stannous chloride dehydrate (2 mg/ mL in 10% acetic acid) was added, and the pH was adjusted to 6.0-6.5 using 50 mM sodium bicarbonate solution.…”