Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)

Grieken, R. Van; Bruin, M. De

doi:10.1351/pac199466122513

Cited by 187 publications

(18 citation statements)

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“…Thet erm specific activity (A S ) can refer to a variety of parameters, although its only meaning, by International Union of Pure and Applied Chemistry definition, is "for a specified isotope, or mixture of isotopes, the activity of a material divided by the mass of the material" (1). In terms of radiolabeled compounds, A S usually describes the activity of the radiolabeled compound divided by the mass of the radioactive and nonradioactive, cold reference compound, for example, a small molecule, a peptide, or an antibody fragment (2).…”

mentioning

confidence: 99%

Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃

et al. 2016

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68 Ga-aquibeprin and 68 Ga-avebetrin are tracers for selective in vivo mapping of integrins α 5 β 1 and α v β 3 , respectively, by PET. Because both tracers exhibit high affinity to their respective targets, the aim of this study was to investigate the influence of the specific activity of preparations of both tracers on in vivo imaging results. Methods: Fully automated 68 Ga labeling of 0.3 nmol of aquibeprin or avebetrin was done using buffered eluate fractions (600-800 MBq, pH 2) of an SnO 2 -based generator, affording the radiopharmaceuticals with specific activities greater than 1,000 MBq/nmol. Lower values ranging from 150 to 0.4 MBq/nmol were adjusted by addition of inactive compound (∼0.15-50 nmol) to the injected activity (∼20 MBq for PET, 5-7 MBq for biodistribution). For in vivo experiments, 6-to 12-wk-old female severe combined immunodeficiency mice bearing M21 xenografts (human melanoma, expressing both integrins α 5 β 1 and α v β 3 ) were used. The expression density of integrin β 3 was determined by immunohistochemistry on paraffin slices. Results: For mass doses (specific activities) of less than 20 pmol (.1,000 MBq/nmol) and 1 nmol (20 MBq/nmol) per mouse, respectively, uptake of 68 Ga-aquibeprin and 68 Ga-avebetrin in M21 tumors dropped from 5.3 and 3.5 to 3.0 and 2.4 percentage injected dose per gram (%ID/g), respectively. When less than 20 pmol was applied, high uptake of 68 Gaaquibeprin in the eyes (4.5 %ID/g) or 68 Ga-avebetrin in adrenals (25.9 %ID/g), respectively, were found, which was reduced by 90% and 65% (0.44 and 6.2 %ID/g, respectively), for doses of 1 nmol. The highest tumor-to-tissue ratios were observed both in ex vivo biodistribution and PET for comparably large doses, for example, 6 nmol (0.65 mg/kg) 68 Ga-aquibeprin per mouse (3.5 MBq/nmol). Conclusion: Presumably because of their high affinities, 68 Ga-aquibeprin and 68 Ga-avebetrin allow for selective addressing of target sites with different integrin expression levels by virtue of adjusting specific activity, which can be exploited for visualization of low-level target expression or optimization of tumor-tobackground contrast.

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confidence: 99%

Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃

et al. 2016

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“…The reaction vessel was pre-loaded with 50 μg peptide suspended in 290 μL pH = 4 NaOAc buffer to adjust the final pH to 5.3–5.5; and the reaction vessel was heated at 85 °C for 45 min (conditions optimized previously). (Baidoo, Milenic et al, 2013) Radiolabeling efficiency (the percentage of incorporated radionuclide from radiolabeling reaction) and radiochemical purity (the fraction of the stated isotope present in the stated chemical form) (Grieken and de Bruin, 2009) [ 203 Pb/ 212 Pb]Peptides was analyzed by radio-ITLC and radio-HPLC method (Supplemental material). Separation/isolation of radiolabeled DOTA-conjugates from unlabeled peptide via HPLC was also investigated (Supplemental material).…”

Section: Methodsmentioning

confidence: 99%

Automated cassette-based production of high specific activity [ 203/212 Pb]peptide-based theranostic radiopharmaceuticals for image-guided radionuclide therapy for cancer

Zhang

Quinn

et al. 2017

Applied Radiation and Isotopes

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A method for preparation of Pb-212 and Pb-203 labeled chelator-modified peptide-based radiopharmaceuticals for cancer imaging and radionuclide therapy has been developed and adapted for automated clinical production. Pre-concentration and isolation of radioactive Pb2+ from interfering metals in dilute hydrochloric acid was optimized using a commercially-available Pb-specific chromatography resin packed in disposable plastic columns. The pre-concentrated radioactive Pb2+ is eluted in NaOAc buffer directly to the reaction vessel containing chelator-modified peptides. Radiolabeling was found to proceed efficiently at 85°C (45min; pH 5.5). The specific activity of radiolabeled conjugates was optimized by separation of radiolabeled conjugates from unlabeled peptide via HPLC. Preservation of bioactivity was confirmed by in vivo biodistribution of Pb-203 and Pb-212 labeled peptides in melanoma-tumor-bearing mice. The approach has been found to be robustly adaptable to automation and a cassette-based fluid-handling system (Modular Lab Pharm Tracer) has been customized for clinical radiopharmaceutical production. Our findings demonstrate that the Pb-203/Pb-212 combination is a promising elementally-matched radionuclide pair for image-guided radionuclide therapy for melanoma, neuroendocrine tumors, and potentially other cancers.

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“…The International Union of Pure and Applied Chemistry (IUPAC) defines the plasma elimination half-life (t ½ ) as follows: 'For a substance, the time required for the amount of that substance in a biological system to be reduced to one half of its value by biological processes, when the rate of removal is approximately exponential' (van Grieken & de Bruin 1994). This means that the plasma half-life of a compound is the time it takes for the blood plasma concentration to decline by one half.…”

Section: Plasma Elimination Half-lifementioning

confidence: 99%

Toxicokinetics and Toxicogenetics

Meyer¹,

Maurer²

2014

Handbook of Forensic Medicine

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Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)

Cited by 187 publications

References 0 publications

Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃

Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃

Automated cassette-based production of high specific activity [ 203/212 Pb]peptide-based theranostic radiopharmaceuticals for image-guided radionuclide therapy for cancer

Toxicokinetics and Toxicogenetics

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Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)

Cited by 187 publications

References 0 publications

Variation of Specific Activities of 68Ga-Aquibeprin and 68Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α5β1 and αvβ3

Variation of Specific Activities of 68Ga-Aquibeprin and 68Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α5β1 and αvβ3

Automated cassette-based production of high specific activity [ 203/212 Pb]peptide-based theranostic radiopharmaceuticals for image-guided radionuclide therapy for cancer

Toxicokinetics and Toxicogenetics

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Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃

Variation of Specific Activities of ⁶⁸Ga-Aquibeprin and ⁶⁸Ga-Avebetrin Enables Selective PET Imaging of Different Expression Levels of Integrins α₅β₁ and α_vβ₃