The quantification of technetium in generator-derived pertechnetate using ICP-MS

Hill, David M.; Barnes, R.K.; Wong, Henri; Zawadzki, Atun

doi:10.1016/s0969-8043(99)00280-8

Cited by 14 publications

(4 citation statements)

References 3 publications

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“…Nevertheless, IC 50 values within the nanomolar to micromolar range indicate that a degree of cytotoxicity is maintained in the complexes. This presents no barrier for the potential radiodiagnostic application of the corresponding 99m Tc complexes because the concentration of 99m Tc formulations in the blood 18 is typically in the picomolar range, orders of magnitude below the IC 50 values of the complexes, and therefore, their administration presents no cytotoxic danger. For the potential radiotherapeutic applications of 2a and 3a with the 186 Re and 188 Re isotopes the possibility for combined radiotherapy/chemotherapy that would exploit both the cytotoxic properties of the radionuclide and those of the 2-(4 0 -aminophenyl)benzothiazole emerges as an attractive concept for further exploration.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

Tzanopoulou¹,

Sagnou²,

Paravatou-Petsotas³

et al. 2010

J. Med. Chem.

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The synthesis of M(I)(CO)(3)(NNO) (M = Re, (99m)Tc) complexes conjugated to the antitumor agent 2-(4'-aminophenyl)benzothiazole and to its 6-methyl derivative, as well as their in vitro and in vivo biological evaluation as breast cancer radiopharmaceuticals, is reported. The Re complexes displayed under the fluorescence microscope clear uptake by the sensitive to the 2-(4'-aminophenyl)benzothiazole pharmacophore breast cancer cell lines MCF-7 and T47D, while uptake by less sensitive lines and by normal fibroblasts was much weaker. In accordance, uptake of the corresponding radioactive (99m)Tc complexes was clearly higher in the breast cancer cell lines MCF-7 and MDA-231 compared to normal fibroblasts. Biodistribution of the (99m)Tc complexes in SCID mice bearing MCF-7 xenografts showed appreciable tumor uptake. A tumor/muscle ratio of 2.2 was measured for the complex conjugated to 2-(4'-aminophenyl)benzothiazole that led to successful tumor imaging. The results render the 2-(4'-aminophenyl)benzothiazole complexes potential candidates for imaging ((99m)Tc) and targeted radiotherapy ((188)Re) of breast cancer.

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Section: Discussionmentioning

confidence: 99%

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

Tzanopoulou¹,

Sagnou²,

Paravatou-Petsotas³

et al. 2010

J. Med. Chem.

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“…For saturation studies, cells were incubated in triplicate with increasing concentrations (1 to 500 pM, equivalent to 2 to 1000 kBq of 99m Tc activity) of the 99m Tc(I)-labeled bombesin analogue for 1 h at 37 °C. The concentrations of active 99m Tc were calculated as described by Bauer and Pabst ( 16) and Hill et al (17). After two washing steps with binding buffer, cells were solubilized with 1 N NaOH at 37 °C.…”

Section: Methodsmentioning

confidence: 99%

A ^99mTc(I)-Postlabeled High Affinity Bombesin Analogue as a Potential Tumor Imaging Agent

García-Garayoa

Bähler

et al. 2002

Bioconjugate Chem.

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The overexpression of neuropeptide receptors observed in many cancers provides an attractive target for tumor imaging and therapy. Bombesin is a peptide exhibiting a high affinity for the gastrin releasing peptide (GRP) receptor, which is overexpressed by a variety of tumors such as breast or prostate cancer. In the present study, we have evaluated if the bombesin analogue [N(alpha)-histidinyl acetate]bombesin(7-14), radiolabeled with the novel [99mTc(OH(2))(3)(CO)(3)]+, has the potential to be used as a diagnostic radiopharmaceutical. Receptor saturation studies, carried out on the GRP receptor-expressing PC-3 human prostate cancer cell line, revealed for [99mTc(CO)(3)-N(alpha)-histidinyl acetate]bombesin(7-14) K(d) values in the subnanomolar range. Competitive binding assays, using the cold rhenium(I)-labeled analogue as a surrogate for the 99mTc-conjugate, also showed high affinity binding. Incubation of the radioconjugate with PC-3 cells resulted in a rapid temperature- and time-dependent specific internalization. At 37 degrees C more than 70% was internalized within the first 15 min and remained constant up to 2 h. Despite the weak proteolytic stability of [99mTc(CO)(3)-N(alpha)-histidinyl acetate]bombesin(7-14) in vitro, biodistribution studies, performed in PC-3 tumor-bearing mice, showed low uptake in the tumor (0.89 +/- 0.27% ID/g 30 min pi) but high uptake into the pancreas (7.11 +/- 3.93% ID/g 30 min pi), a GRP receptor-positive organ. Blockade experiment (coinjection of 300 microg bombesin/mouse with the radioligand) showed specificity of the uptake. Despite the low tumor uptake, tumor-to-blood ratios of 2.0 and 2.7 and tumor-to-muscle ratios of 8.9 and 8.0 were obtained at 30 min and 1.5 h postinjection, respectively. The promising results merit the future in vivo investigation of 99mTc/188Re-tricarbonyl-labeled bombesin analogues.

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“…ICP-MS was also investigated to determine the 99 Tc/ 99m Tc ratios in sodium pertechnetate by Hill et al [23]. It has been recognized for over 20 years that the presence of increased levels of the long-lived radioisotope 99 Tc in solutions of 99m Tc can adversely affect labeling efficiencies of a number of sensitive reagent kits used in nuclear medicine.…”

Section: Quantitative Analysis Of Medicine and Its Metabolitesmentioning

confidence: 99%

The application of inductively coupled plasma mass spectrometry in pharmaceutical and biomedical analysis

Huang

Zhang

et al. 2006

Journal of Pharmaceutical and Biomedical Analysis

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The quantification of technetium in generator-derived pertechnetate using ICP-MS

Cited by 14 publications

References 3 publications

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

A ^99mTc(I)-Postlabeled High Affinity Bombesin Analogue as a Potential Tumor Imaging Agent

The application of inductively coupled plasma mass spectrometry in pharmaceutical and biomedical analysis

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The quantification of technetium in generator-derived pertechnetate using ICP-MS

Cited by 14 publications

References 3 publications

Evaluation of Re and 99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

Evaluation of Re and 99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

A 99mTc(I)-Postlabeled High Affinity Bombesin Analogue as a Potential Tumor Imaging Agent

The application of inductively coupled plasma mass spectrometry in pharmaceutical and biomedical analysis

Contact Info

Product

Resources

About

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

Evaluation of Re and ^99mTc Complexes of 2-(4′-Aminophenyl)benzothiazole as Potential Breast Cancer Radiopharmaceuticals

A ^99mTc(I)-Postlabeled High Affinity Bombesin Analogue as a Potential Tumor Imaging Agent