Search Results
Abstract
A conjugate of 6-hydrazinopyridine-3-carboxylic acid (HYNIC) with the amino analogue of metronidazole (MN) was synthesized through a multiple-step reaction. HYNIC-MN could be labeled easily and efficiently with 99mTc using N-(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)glycine (tricine) and ethylenediamine -N,N′-diacetic acid (EDDA) as coligands to form the 99mTc–HYNIC–MN complex in high yield (>95%). Its partition coefficient indicated that it was a good hydrophilic complex. The tumor cell experiment showed that the 99mTc–HYNIC–MN complex had a certain hypoxic selectivity. The biodistribution studies of 99mTc–HYNIC–MN in Kunming mice bearing S180 tumor showed a favorable tissue distribution profile with high tumor uptake, and low or negligible accumulation in non-target organs, suggesting 99mTc–HYNIC–MN would be a novel potential tumor hypoxia imaging agent.
Abstract
A conjugate of 6-hydrazinopyridine-3-carboxylic acid (HYNIC) with aminomethylenediphosphonic acid (AMDP) was synthesized through a multiple-step reaction. HYNIC–AMDP could be labeled easily and efficiently with 99mTc using N-(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)glycine (tricine) as coligand to form the 99mTc–HYNIC–AMDP complex in high yield (> 95%). Its partition coefficient indicated that it was a good hydrophilic complex. The biodistribution studies of 99mTc–HYNIC–AMDP in normal ICR mice showed that this complex had high bone uptake and low or negligible accumulation in non-target organs. As compared with 99mTc–MDP, 99mTc–HYNIC–AMDP had a higher bone uptake and the ratios of bone/blood and bone/muscle at early time after injection, suggesting that it could be potentially useful for bone imaging at an earlier time after injection according to further investigations of the biological behavior of this complex.
Abstract
The optimization of the radiolabeling yield of ciprofloxacin analogous, norfloxacin, with technetium-99m (99mTc) was described. Dependence of the labeling yield of 99mTc–norfloxacin complex on the concentration of norfloxacin, SnCl2·2H2O content, pH of the reaction mixture and reaction time was studied. Norfloxacin was labeled with 99mTc at pH 3 with a labeling yield of 95.4% by using 5 mg norfloxacin, 50 μg SnCl2·2H2O and 30 min reaction time. The formed 99mTc–norfloxacin complex was stable for a time up to 3 h. Biological distribution of 99mTc–norfloxacin complex was investigated in experimentally induced inflammation rats using Staphylococcus aureus (bacterial infection model) and heat killed Staphylococcus aureus and turpentine oil (sterile inflammation model). In case of bacterial infection, the T/NT value for 99mTc–norfloxacin complex was found to be 6.9 ± 0.4 which was higher than that of the commercially available 99mTc–ciprofloxacin under the same experimental condition.
Abstract
A variety of human tumors like prostate and breast cancer express bombesin receptors. Due to this a new bombesin analogue was labeled with 99mTc via HYNIC and tricine as a coligand and investigated further. Peptide was synthesized on a solid phase using Fmoc strategy. Labeling with 99mTc was performed at 100 °C for 10 min and radiochemical analysis involved ITLC and HPLC methods. The stability of radiopeptide was checked in the presence of human serum at 37 °C up to 24 h. Internalization was studied with the human GRP receptor cell line PC-3. The biodistribution was studied in mice. Labeling yield of >98% was obtained corresponding to a specific activity of ~80.9 GBq/μmol. Radiopeptide internalization into PC-3 cells was moderate and specific (10.7 ± 1.2% at 4 h). A high and specific GRP receptor expressing mouse tumor and pancreas uptake (1.12 ± 0.08 and 1.04 ± 0.11% ID/g after 1 h respectively) was also determined.
Abstract
3-Amino-2-quinoxalincarbonitrile 1,4-dioxide (AQCD) is a quinoxaline derivative, which was synthesized by condensation method. AQCD was labeled with 99mTc with labeling yield above 90% investigated by paper chromatography. 99mTc-AQCD was prepared using stannous chloride as reducing agent at pH 7 and 10 min reaction time. 99mTc-AQCD should be freshly prepared, otherwise the yield significantly decreased after 15 min post labeling. Stability study of 99mTc-AQCD reflected the short time stability of Biodistribution study of 99 mTc-AQCD in tumor bearing mice reflected that its uptake in tumor sites in both ascites and solid tumor sites. This uptake of 99mTc-AQCD in tumor sites was sufficient to radioimage the inoculated sites.
Abstract
The dimercaptosuccinic acid metronidazole ester (DMSAMe) was synthesized and radiolabeled with 99mTc to form the 99mTc-DMSAMe complex in high yield. The radiochemical purity of the 99mTc-DMSAMe complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The tumor cell experiment and the biodistribution in mice bearing S 180 tumor showed that the 99mTc-DMSAMe complex had a certain hypoxic selectivity and accumulated in the tumor with high uptake and good retention. The tumor/blood and tumor/muscle ratios increased with time, suggesting it would be a possible tumor hypoxia imaging agent.
Abstract
Easy and efficient way to modify of the C-terminus of the peptide using amino acid lysine has been proposed and experimentally verified. The synthesis yield was high (≥85%) and it was found that reactions can be carried out even with microgram amounts of the peptide. Using Fmoc-alanine (as the peptide model) with modified C-terminus the procedure of peptide labelling with monovalent and trivalent 99mTc complexes has been elaborated.
Abstract
7-Bromo-1,4-dihydro-4-oxo-quinolin-3-carboxylic acid (BDOQCA), was synthesized with a yield of 93% and well characterized. The obtained compound was investigated to label with one of the most important radioactive isotopes (technetium-99m). Effect of BDOQCA concentration, stannous chloride dihydrates (SnCl2.2H2O) concentration, pH and reaction time on the percent labeling yield of 99mTc-BDOQCA complex was studied in details. 99mTc-BDOQCA complex was obtained at a maximum yield of 97.3% by mixing 2.5 mg of BDOQCA with 25 μg SnCl2.2H2O at pH 6 and 30 min reaction time and the formed complex was stable for a time up to 8 h with a maximum yield of 97.3%. Biodistribution studies in mice were carried out using experimentally induced infection in the left thigh using E. coli. Both thighs of the mice were dissected and counted to evaluate the ratio of bacterial infected thigh/contralateral thigh. Higher uptake in the infected thigh was observed after 2 h of IV administration of 99mTc-BDOQCA complex (T/NT = 7.6 ± 0.6%) than that of the commercially available 99mTc-ciprofloxacin complex (T/NT = 3.8 ± 1%). The in vitro binding and biodistribution of 99mTc-BDOQCA complex in the septic and aseptic inflammation bearing mice showed that, 99mTc-BDOQCA complex is a promising agent for infection imaging and can differentiate between infected and inflamed muscle.
Abstract
Tumors such as prostate, small cell lung cancer, breast, gastric and colon cancer are known to overexpress receptors to bombesin (BBN). In this study, a new bombesin analogue was labeled with 99mTc via HYNIC and tricine/EDDA as coligands and investigated further. HYNIC-GABA-Bombesin (7–14) NH2 was synthesized using a standard Fmoc strategy. Labeling with 99mTc was performed at 100 °C for 10 min and radiochemical analysis involved ITLC and HPLC methods. The stability of radiopeptide was checked in the presence of humane serum at 37 °C up to 24 h. The receptor bound internalization and externalization rates were studied in GRP receptor expressing PC-3 cells. Biodistribution of radiopeptide was studied in nude mice bearing PC-3 tumor. Labeling yield of >98% was obtained corresponding to a specific activity of ~2.6 MBq/nmol. Peptide conjugate showed good stability in the presence of human serum. The radioligand showed high and specific internalization into PC-3 cells (14.63 ± 0.41% at 4 h). In biodistribution studies, a receptor-specific uptake was observed in GRP-receptor-positive organs so that after 4 h the uptakes in mouse tumor and pancreas were 1.31 ± 0.18 and 1.2 ± 0.13% ID/g, respectively.
Abstract
Several chromatographic methods have been used for determining the radiochemical purity of99mTc-phytate. Good separation of99mTc-phytate from radiochemical impurities was performed using gel column chromatography packed with Sephadex G-10. Reduced99mTc-complexes and99mTc-phytate were not separated by paper and thin layer chromatography.
