Radiolabeled metallic complexes

In a study of the bioaccumulation of metals as colloid complexes and free ions by the marine brown shrimp, Penaeus aztecus [29] the colloids were isolated and concentrated from water obtained from Dickinson Bayou, an inlet of Galveston Bay, Texas, using various filtration and ultrafiltration systems equipped with a spiral-wound 1 kDa cutoff cartridge. The total colloidal organic carbon in the concentrate was found to be 78 lmgdm 3. The shrimps were exposed to metals (Mn, Fe, Co, Zn, Cd, Ag, Sn, Ba and Hg) as radiolabelled colloid complexes, and free-ionic radiotracers using ultrafiltered seawater without radiotracers as controls. The experiments were designed so that the animals were exposed to environmentally realistic metal and colloid concentrations. 

DOTA is of particular interest as a BFC for radiolabeling of small BMs with yttrium and lanthanide isotopes. The macrocyclic framework is well organized so that it forms yttrium and indium complexes with high thermodynamic stability and kinetic inertness. The pXa values of the carboxylic groups are in the range 2-5. Lower pKa values result in less competition from protons, high stability of the metal complex, and minimum acid-assisted demetallation, even... 

Our study of the in vivo distribution of all six chloroammlne-platlnum(II) complexes has been completed and represents, to the best of our knowledge, the first blodlstrlbutlon study of a complete series of transition metal complexes. The purposes of this paper are to report (a) a brief description of the microscale synthesis of the t-radiolabeled complexes, (b) the empirical... 

Section 7.4), include Co(n) and Co(III) [18-22], Mn(II) [23, 24], Zn(II) [25, 26], Ni(H) [27], Ru(III) [28], Tc [29], and V(IV) [30]. Earlier results have been summarized [3]. Many of these examples may be considered to be attempts at producing tumour-localizing agents, combining the known affinity of bleomycin for tumour cells with a suitably stable metal radiolabel. The metallation does appear to affect tissue distribution, which may imply an alteration in functional structure of the drug. A study of the cytotoxic and antitumour properties of some metal complexes gave an order of activity in culture and antitumour potency of Cu(II)BLM > BLM >Zn(II)BLM >Fe(III)BLM Co(II)BLM [31]. 

One attraction of the homogeneous ZN-catalyst is that it may contain a single well-defined transition metal complex as the catalytic species. This was the motivation of our earlier investigation of the Cp2TiCl2/AlR2Cl catalyst. However, the heterogeneity in the microstructures of anl-PP and the radiolabeling determination of c distrlbution showed that there are two or more catalytic species in the ansa-metallocene/MAO systems. 

Other advantages of PET imaging with metallic radionuclides are facile radiolabeling (i.e. certain 64Cu complexes radiolabel in less than lmin at room temperature (12)) and generator availability (for 68Ga). 

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