Radiolabeled fatty acids as myocardial metabolic agent are used for detecting ischemic heart disease, however, no 99mTc-labeled fatty acids have potential use in clinical diagnosis. In this work, five fatty acid analogues labeled with 99mTc were firstly synthesized and characterized, their biological behaviors were investigated. All Radiotracers had good stability when incubated in rat serum for 3 h at 37 °C. 99mTc -CpT-12-ODPPA (8b) showed higher initial myocardial uptake (8.17% ID/g at 1 min postinjection) and good heart/blood ratio (2.58 at 30 min postinjection). 99mTc-11-dpa-OUFA (2b) as positively charged lipophilic compounds had reasonable heart uptake (5.59% ID/g at 1 min postinjection) and good retention (1.89% ID/g at 60 min postinjection). Unfortunately, no great improvement was obtained by the five 99mTc-labeled fatty acid analogues for the short myocardial retention and poor heart/liver ratios.

Fatty acids are myocardial metabolic agent for detecting myocardial ischemia and infraction. However, no 99m Tc-labeled fatty acids had potential use in clinical practice. In this study, 99m Tc-CpTT-10-oxo-para-PPA (1d), 99m Tc-CpTT-11-oxo-para-PPA (2d), 99m Tc-CpTT-12-oxo-para-PPA (3d), 99m Tc-CpTT-11-oxo-ortho-PPA (4d), and 99m Tc-CpTT-11-oxo-meta-PPA (5d) were synthesized by a double ligand transfer reaction, and their biological behaviors were investigated. Compound 2d achieved good heart to blood ratio (3.39 at 5 min after intravenous), and 2d showed high-heart uptake of 6.20% ID/g at 5 minutes after injection. Compound 3d displayed a prolonged retention in the myocardium (1.43% ID/g at 60 min after injection). Radioactivity accumulation in the lungs, spleen, and blood was eliminated rapidly. In vivo, metabolite analysis presented that compound 6d may be metabolite of 2d through β-oxidation in tissue. Unfortunately, the biodistribution studies of 1d, 2d, 3d, 4d, and 5d showed fast heart clearance and poor heart to liver ratios, which suggested that the 5 99m Tc-labeled fatty acid analogues cannot be used for diagnosis.

Six novel long chain fatty derivatives with dipicolylamine ligand were designed and synthesized and incorporated with fac-[99mTc(CO)3]+ as potential myocardial metabolic SPECT agents. They were prepared in a radiolabeling yield and demonstrated positively charged. The chemical stability of these compounds were good. Biodistribution studies were performed in normal mice, all compounds showed good initial heart uptake and retention, for 1b the heart uptake was 3.28 %ID/g at 1 min and could keep with 1.11 %ID/g at 60 min, it also showed a rapid blood clearance (blood1 min/blood60 min = 28).

11C, 18F and 123I fatty acids are used for myocardial imaging, and 99mTc‐labeled fatty acids are more desirable substitutes than other radiolabeled fatty acids. In the work reported, [99mTc]‐CpTT‐10‐oxo‐FPA (1c), [99mTc]‐CpTT‐12‐oxo‐FPA (2c), [99mTc]‐CpTT‐14‐oxo‐FPA (3c) and [99mTc]‐CpTT‐16‐oxo‐FPA (4c) were prepared with 60.76–70.92% of radiochemical yield and purity of more than 95%. These radiotracers (1c, 2c, 3c, 4c) were chemically stable when incubated in Sprague Dawley rat serum for 3 h at 37 °C. Tissue distribution studies in female mice indicated that 2c had high initial heart uptake (8.84%ID g−1 at 1 min post‐injection) and 4c had long retention in the heart (1.45%ID g−1 at 30 min post‐injection). Metabolite analysis showed 4c could be metabolized to 5c via β‐oxidation with loss of two CH2 in the myocardium, the radiometabolite being excreted via urine. However, low heart uptake suggested that 4c cannot be used as a diagnostic imaging agent. Copyright © 2016 John Wiley & Sons, Ltd.

Extraction complexes of Eu(III), Tb(III), Tm(III), and Am(III) with three 1,10-phenanthroline-type ligands have been studied, primarily using density functional theory (DFT). The same accuracies and optimized structural geometries were obtained whether optimization of the [ML2(NO3)](2+) complexes was performed at the B3LYP/6-31G(d)/RECP or the MP2/6-31G(d)/RECP level of theory. Calculations carried out at the B3LYP/6-311G(d, p)/RECP level of theory indicated that solvation does not favor the formation of these complexes. Moreover, the ΔGg and ΔGsolv values for the reactions leading to the formation of [LnL2(NO3)](2+) complexes were seen to decrease with increasing atomic number of the lanthanide (from Eu to Tb to Tm). In addition, when a strongly hydrophobic benzo[e][1,2,4]triazine group was created in each ligand, ligand selectivity for actinides/lanthanides in acidic media improved. Even greater ligand selectivity for actinides/lanthanides in acidic media was obtained when a 5,6-diphenyl-1,2,4-triazine group was created in each ligand instead of a benzo[e][1,2,4]triazine group. Vibrational analysis and NMR spectroscopic analysis were also performed on all of the studied ligands and the metal complexes that included them. Further in-depth investigations should be undertaken in this field.

We investigated the extraction complexes of Eu(III) and Am(III) with two 1,10-phenanthroline-type ligands primarily using density functional theory (DFT). The geometrical optimizations of the structures of the [ML2NO3]2+ species, can achieve the same accuracy and obtain the same geometrical configuration at both the B3LYP/6-31G(d)/RECP and MP2/6-31G(d)/RECP levels of theory. At the B3LYP/6-311G(d,p)/RECP level of theory, solvation is unfavorable to the formation of the complexes. However, it is the solvation that make the separation between the [AmL2(NO3)]2+ complexes and the [EuL2(NO3)]2+ complexes. Additionally, the introduction of strong hydrophobic substituents into ligands improves their selectivity for actinide/lanthanide in acidic media.