• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.83-88
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• 2019

In order to understand the in vivo biodistribution of repebody protein (RB), an efficient and simple radiolabeling method for the protein is needed. We demonstrate a detailed protocol for the radiosynthesis of an ¹¹¹In radiolabeled tetrazine prosthetic group and its application to the efficient radiolabeling of trans-cyclooctene-group conjugated repebody protein using inverse-electron-demand Diels-Alder reaction. First, 1,2,4,5-tetrazine (Tz) conjugated with a DOTA chelator, was used for preparing the radiolabeled DOTA complex with ¹¹¹In. Second, the trans-cyclooctene (TCO) functionalized repebody protein was synthesized which allows for the preparation of radiolabeled proteins by copper-free click chemistry. Following incubation with the ¹¹¹In-radiolabeled DOTA complex (¹¹¹In-Tz), the TCO-functionalized RB (TCO-RB) was radiolabeled successfully with ¹¹¹In, with a high radiochemical yield (69.5%) and radiochemical purity (>99%). The radiolabeling of repebody protein by copper-free click chemistry was accomplished within 20 min, with great efficiency in aqueous conditions. These results clearly indicate that the present radiolabeling method will be useful for the efficient and convenient radiolabeling of trans-cyclooctene-group containing biomolecules.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.103-107
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• 2016

Solid phase extraction (SPE) purification method is the efficient and well-known tool for automated [$^{11}C$]acetate synthesis. A fully automated homemade module adopting the SPE method and 'pinch' valves was developed very economically with a universal interface board, a relay card and an open source programmable logic controller. The radiochemical yield of the optimized [$^{11}C$]acetate synthesis by this system was $58.8{\pm}2.1%$ (n=10, decay-corrected) from $15.5{\pm}0.19GBq$ of $[^{11}C]CO_2$ as starting activity, and total synthetic time was 15 minutes. HPLC analysis showed its high radiochemical purity as $97.4{\pm}1.1%$ without possible by-products.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.595-598
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• 2008

Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) is a natural chemotherapeutic compound with diverse biological properties including an antitumor activity. Emodin, a specific inhibitor of the protein tyrosine kinase, has a number of cellular targets in related to it. Its inhibition activity affects the mammalian cell cycle regulation in specific oncogene. Practically, it has been proven to inhibit HER-2/neu tyrosine kinase expressing breast cancer cells as an anticancer agent. 2-[123I]iodoemodin has been synthesized and evaluated human breast cancer cells (MDA-MB-231, MCF-7, fibroblast as a control) which express basal levels of HER-2/neu tyrosine kinase to investigate its suitability as a breast cancer imaging agent and 2-iodoemodin has been synthesized as a standard compound. The radiochemical yield of the 2-[123I]iodoemodin was about 72% and its radiochemical purity was over 97% after purification. The radioactivity of the 2-[123I]iodoemodin was increased in a time dependent manner in both cell lines and the ratio of MDA-MB-231 and MCF7 to fibroblast was 2.9 and 1.7, respectively.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.2
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• pp.90-94
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• 2018

The potential health risk from inhalational exposure of diesel exhaust particulates (DEP) has gained considerable scientific interests. However, the long-term in vivo behavior of DEP have not been clearly understood due to the difficulty of accurate analysis of these substances in a living subject. We herein demonstrate a detail protocol for the preparation of radiolabeled DEP using a radioactive-iodine-tagged pyrene analog. The purified $^{125}I$-labeled pyrene ($[^{125}I]1$) was obtained with a good radiochemical yield ($32{\pm}4%$, n=3) and high radiochemical purity (>99%) from the stannylated precursor 2. Next, the purified $[^{125}I]1$ was successfully assembled into the DEP suspension in an efficient manner. The radiolabeled DEP was highly stable in a mouse serum for 7 days without significant deiodination or dissociation of $[^{125}I]1$. These results clearly indicate that the present radiolabeling method will be useful for biodistribution study of carbonaceous particulates in vivo.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.1
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• pp.3-8
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• 2022

Alteration of the mGluR5 density is closely related to various brain diseases including schizophrenia, depression, Parkinson's disease, and Alzheimer's disease. Therefore, mGluR5 is considered as a valuable imaging biomarker for brain disease and many radiopharmaceuticals have been developed so far. Among them, [¹⁸F]FPEB has favorable pharmacokinetic characteristics, and this is the most frequently used radiopharmaceutical for preclinical and clinical studies. In the present study, we want to introduce the optimized radiosynthetic method for the routine production of [¹⁸F]FPEB using a GE TRACERlabTM FXFN pro module. In addition, the entire process was monitored with a webcam to solve the problems arising from the synthetic process. As a result, [¹⁸F]FPEB was prepared by nucleophilic substitution from its nitro- precursor at 120℃ for 20 min in dimethyl sulfoxide. Radiochemical yield was 13.7 ± 5.1% (decay-corrected, n = 91) with the molar activity of 84 ± 17 GBq/µmol at the end of synthesis. The radiochemical purity was determined to be above 96%. The manufactured [¹⁸F]FPEB injection for quality controls were carried out in accordance with an KIRAMS approved protocol, as per ICH and USP guidelines.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.71-83
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• 1989

For the development of $^{99m}Tc-labelled$ antimony sulfide colloid and hydroxyethyl starch, various experiments such as preparation of colloid, control of the distribution of particle size, establishment of labelling conditions, determination of labelling yield and radiochemical purity, examination of stability, and organ imagings of rabbits etc. were carried out. 1) Antimony sulfide colloid was readily prepared by the reaction of aqueous solution of antimony potassium tartrate with hydrogen sulfide generated by treating ferrous sulfide with dilute sulfuric acid. The colloid could be stabilized by adding small amount of polyvinylpyrrolidone. 2) Electron microscopy analysis exhibited the distribution of colloid size in the range of $1\sim15nm$ with a major portion of 9 m. The colloid solution was sterilized by membrane filtration $(0.2{\mu}m)$ and then stored at $4^{\circ}C$. This sterilized colloid was so stable that it was usable at least for one year. 3) The antimony sulfide colloid was labelled by adding sodium $pertechnetate-^{99m}Tc$ solution to the reaction vial, followed by adding hydrochloric acid and then boiled for 30 min. The optimal pH of the reaction mixture was found to be in the range of $1.3\sim1.4$. Instant thin layer chromatography (ITLC) analysis showed high labelling yield of above 99.5%. This labelled colloid maintained high radio-chemical purity of above 99% until 10 hours after labelling. 4) Animal studies showed high uptake of $^{99m}Tc-Sb_2S_3$ colloid at lymph vessels and nodes indicating a suitable agent for lymphoscintigraphy. Satisfactory results were also abtained in other clinical studies. 5) Hydroxyethyl starch (HES $0.6\sim1.0%$) was labelled with $Na^{99m}TcO_4$ in the presence of $SnCl_2$ with high labelling yield of above 99.5%. The optimal pH of the reaction mixture was in the range of $1.8\sim2.0$. $^{99m}Tc-HES$ maintained high radiochemical purity of above 99% until 10 hours after labelling. 6) Animal studies showed that $^{99m}Tc-HES$ migrated more rapidly from the injection sites into the lymph vessels than $^{99m}Tc-Sb_2S_3$ colloid while less amount of the former was uptaken at lymph nodes than that of the latter. Similar phenomenon was also observed in other clinical studies. As a result, $^{99m}Tc-Sb_2S_3$ colloid was found to be more effective lymphoscintigraphic agent than $^{99m}Tc-HES$.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.145-149
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• 1979

The radiochemical purity of $^{14}C(U)-glucose$ solution to be injected to normal laying hen was investigated for studying biokinetics of carbohydrate and lipid metabolism. The liquid scintillation counter was employed for determining the activity of carbon-14. The barium hydroxide and zinc sulfate were adopted to precipitate the protein in the solution. The glucose content in the solution was observed as 0.912 mg per ml, applying Hultman's method. The specific activity of $^{14}C(U)-glucose$ solution was known as 31.3 nCi/mg glucose. The glucose pentaacetate was synthesized to isolate the pure glucose from the solution. The specific activity of pure glucose was measured as 28.5 nCi/mg glucose. Therefore, it was known that the radiochemical purity of the solution was 82.7%.

• Environmental Analysis Health and Toxicology
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• v.1 no.1
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• pp.77-80
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• 1986

Radiochemical synthesis of $N^{G}$-mono［$^{14}$ C-methyl］-L-arginine is described. The compound was synthesized from radio-active mono［$^{14}$ C］-methylamine as easily and purified by strong cation-exchange resin (NH form) liquid chromatography using a gradient of ammonium hydroxide, and crystallized as flavianate. The free amino acid was successfully prepared by strirring its flavianate and strong anion-exchange resin (OH- form), which could remove the flavianic acid from its salt in water below room temperature. Purity of the compound was tested by thin-layer chromatography, thin-layer electro-phoresis, and scintillation spectrometry.y.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.10 no.1
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• pp.42-48
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• 1984

The comparative detergency of Sodium dodecyl sulfate (SDS) solution near the first critical micelle concentration (CMC) was measured by means of a 131 I-labelled castor oil as a soil. More than 95% radiochemical purity of 131 I-labelled castor oil was obtained using potassium lidide as a carrier. Polyester test fabric was soiled with 131 I-labelled castor oil, and washed in a conventional washing apparatus mounted on appropriate devices. Fabric radioactivities were measured before and after washing by a scintilation counter. Near the first CMC, the detergency of SDS was increased with decreasing of surface tension of SDS. It was also shown that 131 I-labelled castor oil was useful for studying the detergency of SDS.

• Advances in nano research
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• v.10 no.5
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• pp.461-470
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• 2021

Infection is one of the major mortality causes throughout the globe. Nuclear medicine plays an important role in diagnosis of deep infections such as osteomyelitis, arthritis infection, heart valve and heart prosthesis infections. Techniques such as labeled leukocytes are sensitive and selective for tracking the inflammations but they are not suitable for differentiating infection from inflammation. Anionic linear-globular dendrimer-G₂ was synthesized then conjugation to gemifloxacin antibiotic. The structures were identified by FT-IR, ¹H-NMR, C-NMR, LC-MS and DLS. The toxicity of gemifloxacin and dendrimer-gemifloxacin complex was compared by MTT test. Dendrimer-G₂-gemifloxacin was labeled by Technetium-99m and its in-vitro stability and radiochemical purity were investigated. In-vivo biodistribution and SPECT imaging were studied in a rabbit model. Identify and verify the structure of the each object was confirmed by FT-IR, ¹H-NMR, C-NMR and LC-MS, also, the size and charge of this compound were 128 nm and -3/68 mv respectively. MTT test showed less toxicity of the dendrimer-G₂-gemifloxacin than free gemifluxacin (P < 0.001). Radiochemical yield was > %98. Human serum stability was 84% up to 24 h. Biodistribution study at 50 min, 24 and 48 h showed that the complex is significantly absorbed by the intestine and accumulation in the lungs and affects them, finally excreted through the kidneys, biodistribution results are consistent with results from full image means of SPECT/CT technique.