共查询到20条相似文献,搜索用时 31 毫秒
1.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(8):831-840
The binding of 99mTc to negatively-charged and neutral unilamellar lipid vesicles was investigated in the absence and presence of the ligand diethylenetriaminepentaacetic acid (DTPA) covalently attached to the headgroup of phosphatidylethanolamine at the surface of the membrane. Even in the absence of DTPA on the membrane surface, 99mTc reduced by Sn bound to the membrane surface but rapidly dissociated from the vesicles in the presence of plasma in vitro. When DTPA was present on the membrane surface, dissociation of 99mTc from the vesicle surface in plasma was much reduced. The dissociation of 99mTc from the surface of negatively-charged vesicles was less than for neutral vesicles in the absence of ligand but was markedly greater than for vesicles containing the ligand DTPA, suggesting that the binding of 99mTc to vesicles with surface-attached DTPA could not be explained solely on the basis of the negative charge provided by the DTPA. In vitro experiments using 14C-labeled lipids as well as in vivo imaging studies indicated that dissociation of 99mTc from the surface of the vesicle did not arise predominantly because of lipid exchange with plasma components or due to cleavage of Tc-DTPA from the vesicle surface. For vesicles with surface-attached DTPA, 99mTc dissociation from the vesicle surface in plasma was further reduced by addition of the antioxidant ascorbate. 相似文献
2.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(7):741-746
A simple procedure for the preparation of 99mTc—carbonyl complexes of dithiocarbamates in high yield and radiochemical purity has been developed and used for the preparation of 99mTc—carbonyl complexes of bis(2-hydroxyethyl)dithiocarbamate and bis(2-hydroxypropyl)dithiocarbamate. These complexes were found to be extremely stable and their biological behaviour was studied in mice and compared to that of the 99mTcN- and the 99mTc-complexes [prepared by dithionite (dit) reduction] of the same ligands. The carbonyl complexes were found to be efficient hepatobiliary agents and cleared more rapidly than the corresponding 99mTcN- and 99mTc(dit)-complexes. 相似文献
3.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(7):791-795
Diaminedithiols (DADT) are known to form neutral-lipophilic complexes with 99mTc in aqueous solutions, where they are readily formed in high yields and demonstrate excellent stability. A new triaminedithiol (TADT) ligand was synthesized, characterized and shown to form a neutral-lipophilic 99mTc-chelate. The biodistribution of this 99mTc chelate in rats showed that its uptake in brain or heart following i.v. injection of the 99mTc chelate was low, but activity taken up was retained over a long period of time. The in vivo and in vitro properties of this chelate indicate the possibility that chemical modification of this TADT ligand may produce ligand systems that form 99mTc chelates with suitable diagnostic properties. 相似文献
4.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1989,16(8):829-837
Two new ligand systems for complexation with 99mTc were prepared. The two analogs of bisaminoethanethiol (BAT): N,N′-bis(2-methyl-2-mercaptopropyl)-2,2-dimethylpropylenediamine (PAT-HM) and N,N′-bis[2-(2-ethyl-1-mercaptopropyl)] ethylenediamine (TMR), form neutral and lipid soluble complexes with 99mTc that readily penetrate the blood-brain barrier following i.v. injection into rats. Although the 99mTc chelates do not display the prolonged brain retention required for use in single photon emission computed tomographic imaging studies, the fact that each ligand forms a neutral and lipid-soluble complex of high chemical stability when coordinated with 99mTc warrants further investigation to increase the site- and organ-specificity of these agents. 相似文献
5.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(5):461-468
Platelets pretinned with a neutral Sn(II)-2-mercaptopyridme-N-oxide (SN-MPO) were labeled with 99mTc and compared to those labeled with 99mTc-HMPAO. The conditions of labeling platelets, e.g. concentrations of platelets and Sn(II)-MPO, 99mTc in ACD-saline or ACD-plasma media, pH and incubation time, were optimized using canine platelets. Moderate labeling efficiency was obtained with 20 μg of tin(II) chloride and 30 min incubation with Sn-MPO and pertechnetate. The viability of labeled platelets was determined by platelet recovery and platelet survival times in Beagle dogs. The labeling efficiency with platelets from 43 mL of blood was 62.8 ± 7.6%. The platelet recovery was 35.7 ± 5.0% and exponential survival time was 34.6 ± 3.1 h compared to 43.3 ± 12.0% and 29.5 ± 3.3 h for 99mTc-HMPAO-labeled platelets. These values were significantly (P < 0.01) lower than 111In-labeled platelets. Biodistribution in dogs indicates lower retention in blood, spleen and liver after some initial 99mTc excretion in urine. The platelet deposition with 99mTc platelets (Sn-MPO method) on polyurethane angio-catheters was similar to 99mTc-HMPAO-labeled platelets. This study indicates that the platelets could be successfully labeled with pertechnetate in a cost-effective manner for the evaluation of thromboembolic complications. 相似文献
6.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1989,16(3):283-289
Mannitol has been labelled with 99mTc by using cuprous chloride as a reducing agent. Blood and kidney clearance of 99mTc(Cu)-mannitol was slightly faster than that of 99mTc(Sn)-DTPA in rat and maximum radioactivity ratio of kidneys to blood was 84.6 at 5 min. A comparative study of 99mTc(Cu)-mannitol, 99mTc(Sn)-DTPA was made in rabbits by taking serial images of kidneys and bladder with a γ camera. Results show superiority of 99mTc(Cu)-mannitol over other agents for dynamic renal function studies. 相似文献
7.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1986,13(4):465-477
The β emitting isotopes 186Re and 188Re are logical choices on which to base therapeutic radiopharmaceuticals that might be expected to be analogous to diagnostic radiopharmaceuticals based on 99mTc. However, the chemistry of rhenium is sufficiently different from that of technetium so that the development of Re radiopharmaceuticals often cannot be predicated on the known chemistry and biological behavior of 99mTc radiopharmaceuticals. The relevant chemical differences involve the greater stability of the higher oxidation states of Re (and thus the greater tendency of reduced Re radiopharmaceuticals to undergo re-oxidation to perrhenate), and the greater substitution inertness of reduced Re complexes. These differences are illustrated (1) in the preparation and use of 186Re (Sn)-HEDP and 99mTc(Sn)-HEDP diphosphonate radiopharmaceuticals designed, respectively, for palliative therapy and diagnosis of metastatic cancer to bone, and (2) in the preparation and biodistribution of tr-[186Re(DMPE)2Cl2]+ and [186Re(DMPE)3]+, analogs to the potential myocardial perfusion imaging agents tr-[99mTc(DMPE)2Cl2]+ and [99mTc(DMPE)3]+. [HEDP = (1-hydroxyethylidene)diphosphonate; DMPE = 1,2-bis(dimethylphosphino)ethane]. 相似文献
8.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1987,14(6):555-561
Previously we investigated the use of DTPA-coupled proteins to simplify labeling with 99mTc but especially to improve the stability of the label. These investigations have now been extended to include several N2S2 ligands such as N,N′-bis(2-methyl-2-mercaptopropyl)ethylenediamine (DADT) and a novel ligand of similar structure with a propylene bridge between two amines, 2-hydroxy-N,N′-bis(2-methyl-2-mercaptopropyl)propylenediamine (DADT-3C-2OH). The condition of labeling of free ligand (pH, buffer and tin concentration) was optimized to provide 100% chelation with 99mTc at reasonable ligand concentrations (100 μg/mL or less). Labeling was determined by paper chromatography, reverse-phase and size-exclusion HPLC. After incubation in fresh serum, 37 °C for 24 h, repeat analysis showed less than 5% dissociation of the chelate. By contrast, the DTPA chelate shows instability towards oxidation during this period. DADT derivatized on an ethylene carbon showed almost identical serum stability as DADT itself whereas when derivatized on a nitrogen greater instabilities were apparent. Using identical labeling conditions, free DADT was chelated in the presence of IgG at different ligand: protein molar ratios. Non-specific binding of 99mTc to IgG at a 10:1 DADT-HM:IgG molar ratio was as little as 5% and was essentially zero at a 2:1 DADT:IgG molar ratio when labeling was by transcomplexation from 99mTc-EDTA. The DADT-3C-2OH ligand showed superior performance both in regard to serum stability and the absence of non-specific binding. In conclusion, the N2S2 ligands form more stable chelates with 99mTc than does DTPA with reduced non-specific binding and may therefore represent an attractive alternative for labeling proteins with 99mTc by the bifunctional chelate approach. 相似文献
9.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(6):679-684
Tc-99m monocationic mixed ligand complexes of phenyl substituted/condensed Schiff's bases, N,N′-ethylene-bis-(benzoylacetone imine) (Lb) or N,N′-ethylene-bis-(salicylaldehyde imine) (Lc) or N,N′-ethylene-bis-(2-hydroxyacetophenone imine) (Ld) and trimethylphosphine were synthesized to determine the influence of the presence of a phenyl group in these tracers on their heart uptake in rats. A new formulation procedure using aq. β-hydroxypropylcyclodextrin (HPB) solution was developed for intravenous administration of nonpolar 99mTc complexes. Comparison of biodistribution data for the reference 99mTc complex from N,N′-ethylene-bis-(acetylacetone imine) and trimethylphosphine using HPB formulation and alternate formulation (0.9% saline) showed the same results. Biodistribution of the title 99mTc complexes, [99mTc Lb (PMe3)2]+, [99mTc Lc (PMe3)2]+ and [99mTc Ld (PMe3)2]+ showed heart-to-blood activity ratios of 1.7, 2.1 and 1.7, respectively, at 15 min post-injection in rats. 相似文献
10.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1987,14(1):37-41
The preparation of 99mTc(Sn)HMDP was investigated as a function of pH, Sn(II) and ligand concentration. HMDP could be labeled efficiently from pH 2–9. The Sn(II) and the ligand concentrations had a beneficial influence.The composition of the radiopharmaceutical under various experimental conditions was studied by means of gel chromatography on Biogel P-4. Six different complexes were found. A preparation consisted of maximally three major complexes. The presence of a particular complex was mainly determined by pH and ligand concentration. The Sn(II) concentration had little influence. 相似文献
11.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(5):551-556
In developing new ligands as potential brain and heart perfusion imaging agents two ligands based upon N2S2 donor atoms with the biphenyl backbone were synthesized. Biphenyl-2,2′-bis(N-1-amino-2-methyl-propane-2-thiol) (BP-BAT-TM) and biphenyl-2,2′-bis(N-1-amino-2-ethyl-butane-2-thiol) (BP-BAT-TE) form stable, neutral and lipid soluble complexes with [99mTc]pertechnetate in the presence of tin(II) tartarate as a reducing agent. The [99mTc]BP-BAT-TM complex penetrates the blood-brain barrier following i.v. injection into rats. Washout from the brain is fast, indicating no retention. The biodistribution of [99mTc]BP-BAT-TE in rats showed an intitial heart uptake (0.8% /organ, at 2 min) and a slow washout (0.74% at 15 min). No brain uptake was found (0.05%). Significant uptake and retention in liver was observed. An imaging study of [99mTc]BP-BAT-TE in a monkey showed no brain uptake and a clear indication of liver uptake and gall bladder clearance. These results indicate that this ligand system may be suitable as the basic core structure for the development of new imaging agents. Further studies with structural variations in the biphenyl backbone are warranted to develop new 99mTc imaging agents for clinical applications. 相似文献
12.
The uptake of two different preparations of99mTechnetium-methylene diphosphonate in fetal rat calvaria is compared. The localization of99mTc after administration of99mTc(Sn)-MDP and99mTc-MDP showed equal distribution in autoradiography. 相似文献
13.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(4):491-496
99mTc-Complexes of oxine (ox), thiooxine (tox) and 8-hydroxy-5-quinolinesulphonic acid (HQS) were prepared by ligand exchange of 99mTcNCl4− and by stannous and dithionite reduction of 99mTcO4−. HPLC studies showed that the 99mTcN-tox preparation was almost pure TcN(tox)2. 99mTc(Sn)-ox yielded a number of peaks upon HPLC with the major peak being identified as TcO(ox)2Cl. No other Tc-complexes responsible for other chromatographic peaks were identified. Biodistribution studies in mice showed that all complexes except 99mTc-HQS were cleared essentially by the hepatobiliary pathway. The 99mTc-HQS preparations showed increased renal clearance due to the increased aqueous solubility of the complexes resulting from the presence of the sulphonate group on the quinoline ring. 相似文献
14.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1989,16(8):765-770
The biological behaviour of complexes of 99mTc with aminopolycarboxylic and aminocarbohydroxamic ligands EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaacetic acid), EDTAH (ethylenediaminetetraacetohydroxamic acid) and HIDAmH (N-2-hydroxyethyl-N-carboxymethyl-aminoacetohydroxamic acid) was studied in rabbits. The pharmacokinetic parameters determined in intact rabbits were compared with the results obtained in the study of renal and hepatic clearance of the complexes under study. Hepatobiliary excretion, which in [99mTc]EDTA forms 20–30% of the total excreted amount, is of negligible magnitude in the other 99mTc-complexes studied (<2%). Their renal clearance is not influenced by the inhibition of tubular secretion with probenecid. Binding to plasma proteins increases in the order [99mTc]DTPA < [99mTc]EDTA <[99mTc]HIDAmH <[99mTc]EDTAH and the elimination half-life increases in the same order. The value of renal clearance of the complexes studied related to inulin clearance correlates well with the fraction of the free drug in the plasma. In rabbits the complexes under study are excreted mainly by the mechanism of glomerular filtration in the kidney. 相似文献
15.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(7):695-703
Direct labeling involves 99mTc binding to different donor groups on the protein, giving multiple binding sites of various affinities resulting in an in vivo instability. The stability has been considerably improved by activating the antibody using a controlled reduction reaction (using 2-aminoethanethiol). This reaction generates sulfhydryl groups, which are known to strongly bind 99mTc. The direct 99mTc antibody labeling method was explored using whole antibodies and fragments. Analytical methods were developed for routine evaluation of radiolabeling yield and in vitro stability.Stable direct antibody labeling with 99mTc requires the generation of sulfhydryl groups, which show high affinity binding sites for 99mTc. Such groups are obtained with 2-aminoethanethiol (AET), which induces the reduction of the intrachain or interchain disulfide bond, with no structural deterioration or any loss of immunobiological activity of the antibody. The development of fast, reliable analytical methods has made possible the qualitative and quantitative assessment of technetium species generated by the radiolabeling process. Labeling stability is determined by competition of the 99mTc-antibody bond with three ligands, Chelex 100 (a metal chelate-type resin), free DTPA solution and 1% HSA solution.Very good 99mTc-antibody stability is obtained with activated IgG (IgGa) and Fab′ fragment, which makes these substances possible candidates for immunoscintigraphy use. 相似文献
16.
《Bioorganic & medicinal chemistry》2019,27(11):2245-2252
We have designed (S)-(5-(azetidin-2-ylmethoxy)pyridine-3-yl)methyl cyclopentadienyltricarbonyl technetium carboxylate ([99mTc]CPTT–A–E) with high affinity for nicotinic acetylcholine receptors (nAChRs) using (2(S)-azetidinylmethoxy)-pyridine (A-85380) as the lead compound to develop a Tc-99m-cyclopentadienyltricarbonyl-technetium (99mTc)-labeled nAChR imaging probe. Because technetium does not contain a stable isotope, cyclopentadienyltricarbonyl rhenium (CPTR) was synthesized by coordinating rhenium, which is a homologous element having the same coordination structure as technetium. Further, the binding affinity to nAChR was evaluated. CPTR–A–E exhibited a high binding affinity to nAChR (Ki = 0.55 nM). Through the radiosynthesis of [99mTc]CPTT–A–E, an objective compound could be obtained with a radiochemical yield of 33% and a radiochemical purity of greater than 97%. In vitro autoradiographic study of the brain exhibited that the local nAChR density strongly correlated with the amount of [99mTc]CPTT–A–E that was accumulated in each region of interest. Further, the in vivo evaluation of biodistribution revealed a higher accumulation of [99mTc]CPTT–A–E in the thalamus (characterized by the high nAChR density) when compared with that in the cerebellum (characterized by the low nAChR density). Although additional studies will be necessary to improve the uptake of [99mTc]CPTT–A–E to the brain, [99mTc]CPTT–A–E met the basic requirements for nAChR imaging. 相似文献
17.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1991,18(3):263-274
Substituted monoanilides of nitrilotriacetic acid (NTA) have gained much popularity in recent years as an important class of ligands for technetium-99m (99mTc) radiopharmaceutical preparations used in liver imaging and function studies. We were interested in investigating the properties of the corresponding ester analogues of this important class of ligands and for this study cyclohexanol was selected as a hydroxy component, which on condensation with nitrilotriacetic acid in the presence of acetic anhydride, furnished the monoester, N-cyclohexyloxycarbonylmethyl iminodiacetic acid 4 and the corresponding diester 5. Phenol on similar condensation produced mainly the diester, N, N-di(phenyloxycarbonylmethyl) aminoacetic acid 2, with traces of the corresponding monoester 7. A reinvestigation of the well known condensation reaction of aniline with nitrilotriacetic acid revealed that in addition to the reported monoanilide, N-phenylcarbamoylmethyl imino diacetic acid 3, the corresponding dianilide 6 was also produced in appreciable amount. The ester ligands 2, 4, 5 after 99mTc chelation exhibited good in vitro and in vivo stabilities. The biodistribution characteristics of these radiolabelled esters and amides were very similar showing thereby that esterification with NTA could be an effective method for converting alcohols to 99mTc-radiopharmaceuticals without generating any unusual properties because of the ester linkage. Residual radiopharmaceutical concentration after i.v. administration of these amide and ester 99mTc chelates at 30 min in blood, urine, liver, kidney and intestine were correlated with their lipophilicities and during this correlation it was observed that in addition to lipophilicity the anionic strength of these chelates is also an important determinant in governing their biodistribution. The ester ligand 4 after 99mTc chelation showed ultrafast hepatobiliary kinetics and was therefore compared in a rabbit model with a standard hepatobiliary radiopharmaceutical 99mTc-N-(p-butylphenylcarbamoyl methyl) iminodiacetic acid (99mTc-BIDA) by γ-camera scintigraphy to investigate the potential of the former for clinical studies. 相似文献
18.
Lauren L. Radford Dionysia Papagiannopoulou Fabio Gallazzi Ashley Berendzen Lisa Watkinson Terry Carmack Michael R. Lewis Silvia S. Jurisson Heather M. Hennkens 《Bioorganic & medicinal chemistry》2019,27(3):492-501
The somatostatin receptor subtype 2 (SSTR2) is often highly expressed on neuroendocrine tumors (NETs), making it a popular in vivo target for diagnostic and therapeutic approaches aimed toward management of NETs. In this work, an antagonist peptide (sst2-ANT) with high affinity for SSTR2 was modified at the N-terminus with a novel [N,S,O] bifunctional chelator (2) designed for tridentate chelation of rhenium(I) and technetium(I) tricarbonyl cores, [Re(CO)3]+ and [99mTc][Tc(CO)3]+. The chelator-peptide conjugation was performed via a Cu(I)-assisted click reaction of the alkyne-bearing chelator (2) with an azide-functionalized sst2-ANT peptide (3), to yield NSO-sst2-ANT (4). Two synthetic methods were used to prepare Re-4 at the macroscopic scale, which differed based on the relative timing of the click conjugation to the [Re(CO)3]+ complexation by 2. The resulting products demonstrated the expected molecular mass and nanomolar in vitro SSTR2 affinity (IC50 values under 30?nM, AR42J cells, [125I]iodo-Tyr11-somatostatin-14 radioligand standard). However, a difference in their HPLC retention times suggested a difference in metal coordination modes, which was attributed to a competing N-triazole donor ligand formed during click conjugation. Surprisingly, the radiotracer scale reaction of [99mTc][Tc(OH2)3(CO)3]+ (99mTc; t½?=?6?h, 141?keV γ) with 4 formed a third product, distinct from the Re analogues, making this one of the unusual cases in which Re and Tc chemistries are not well matched. Nevertheless, the [99mTc]Tc-4 product demonstrated excellent in vitro stability to challenges by cysteine and histidine (≥98% intact through 24?h), along with 75% stability in mouse serum through 4?h. In vivo biodistribution and microSPECT/CT imaging studies performed in AR42J tumor-bearing mice revealed improved clearance of this radiotracer in comparison to a similar [99mTc][Tc(CO)3]-labeled sst2-ANT derivative previously studied. Yet despite having adequate tumor uptake at 1?h (4.9% ID/g), tumor uptake was not blocked by co-administration of a receptor-saturating dose of SS-14. Aimed toward realignment of the Re and Tc product structures, future efforts should include distancing the alkyne group from the intended donor atoms of the chelator, to reduce the coordination options available to the [M(CO)3]+ core (M?=?Re, 99mTc) by disfavoring involvement of the N-triazole. 相似文献
19.
Humphrey Fonge Lixin Jin Jan Cleynhens Guy Bormans Alfons Verbruggen 《Bioorganic & medicinal chemistry》2010,18(1):396-402
We have developed four 99mTc(CO)3-labeled lipophilic tracers as potential radiolabeling agents for cells based on a hexadecyl tail. 99mTc(CO)3-hexadecylamino-N,N′-diacetic acid (negatively charged), 99mTc(CO)3-hexadecylamino-N-α-picolyl-N′-acetic acid (uncharged), 99mTc(CO)3-N,N′-dipicolylhexadecylamine (positively charged), 99mTc(CO)3-N-hexadecylaminoethyl-N′-aminoethylamine (positively charged) were prepared in a radiolabeling yield: >90%. Preliminary cell uptake studies were performed in mixed blood cells with or without plasma and were compared with 99mTc-d,l-HMPAO and [18F]FDG. In plasma-free blood cells, maximum uptake (78%) was obtained for 99mTc(CO)3-N-hexadecylaminoethyl-N′-aminoethylamine after 60 min incubation (compared to 55% and 23% for 99mTc-d,l-HMPAO and [18F]FDG, respectively) while in plasma-rich medium, 99mTc(CO)3-N,N′-dipicolylhexadecylamine was best bound (54%, similar to the binding of 99mTc-d,l-HMPAO). Biodistribution in normal mice showed mainly hepatobiliary clearance of the agents and initial high lung uptake. The radiolabeled compounds showed good blood clearance with maximally 7.9% injected dose per gram at 60 min post injection. While the least lipophilic agent (99mTc(CO)3-N,N′-dipicolylhexadecylamine, log P = 1.3) showed the best cell uptake, there appears to be no direct correlation between lipophilicity and tracer uptake in mixed blood cells. In view of its comparable cell uptake to well known cell labeling agent 99mTc-d,l-HMPAO, 99mTc(CO)3-N,N′-dipicolylhexadecylamine merits further evaluation as a potential cell labeling agent. 相似文献
20.
Marina Sagnou Charalambos Triantis Aris Terzis Maria Pelecanou Minas Papadopoulos 《Inorganica chimica acta》2010,363(8):1649-6219
The synthesis and characterization of the neutral 2+1 mixed ligand complex fac-Re(CO)3(acac)(isc) (4) with acetylacetonate (acac) as the bidentate ligand and an isocyanide (the isocyanocyclohexane, isc) as the monodentate ligand is described. The synthesis of 4 proceeds through the intermediate formation of the fac-Re(acac)(H2O)(CO)3 precursor complex 2. Complex 4 was characterized by elemental analysis, spectroscopic methods, and X-ray crystallography showing a distorted octahedral arrangement of the ligands around Re. At technetium-99m level, the corresponding fac-99mTc(acac)(isc)(CO)3 complex 5 was obtained in high yield by reacting the fac-99mTc(acac)(H2O)(CO)3 precursor complex 3 with isocyanocyclohexane and its structure was established by chromatographic comparison with the prototypic rhenium complex using high performance liquid chromatography. 相似文献