Highly efficient technetium-99m labeling procedure based on the conjugation of N-[N-(3-diphenylphosphinopropionyl)glycyl]cysteine ligand with poly(ethylene glycol).

The PN(2)S N-(N-(3-diphenylphosphinopropionyl)glycyl)cysteine ligand was conjugated to methoxy-poly(ethylene glycol)-amino (mPEG-NH(2)) 5 and 20 kDa to yield PN(2)S(Trt)-PEG(5000) 1 and PN(2)S(Trt)-PEG(20000) 2, and then detritylated to PN(2)S-PEG(5000) 4 and PN(2)S-PEG(20000) 5. When an acidic solution of (99m)TcO(4)(-) is added to 4 or 5 in solid form, a quantitative yield in a single labeled species, (99m)Tc-labeled PN(2)S-PEG(5000) 9 and (99m)Tc-labeled PN(2)S-PEG(20000) 10, respectively, is obtained. The reaction occurs in less than 15 min at room temperature for 4 and 35 degrees C for 5.

Technetium-99m labeling of N-[N-(3-diphenylphosphino propionyl)glycyl]cysteine (PN2S-OH) and its methyl ester derivative (PN2S-OMe).

N-[N-(3-diphenylphosphinopropionyl)glycyl]cysteine and its methyl ester derivative were labeled with (99m)Tc at neutral pH, leading to a single species in high yield (>95%) in 30 min. RP-HPLC comparison with the analogue Re(V)-oxo complexes identified the labeled compounds as the anti isomers of pentacoordinated (99m)TcO[PN(2)S]-OH and (99m)TcO[PN(2)S]-OMe complexes. The compounds are stable from pH 7 to pH 9 when (99m)TcO[PN(2)S]-OH interconverts to related syn isomer, while (99m)TcO[PN(2)S]-OMe undergoes both saponification and interconversion.

Infection detection in mice using 99mTc-labeled HYNIC and N2S2 chelate conjugated to the antimicrobial peptide UBI 29-41.

Earlier we reported that UBI 29-41, a synthetic peptide corresponding to residues 29-41 of human ubiquicidin, directly labeled with technetium-99m ((99m)Tc-UBI 29-41) distinguishes bacterial and fungal infections from sterile inflammations in animals. This study was undertaken to evaluate the radiochemical and biological characteristics of (99m)Tc-UBI 29-41 labeled through the intermediacy of a HYNIC or N(2)S(2) moiety, which were introduced at the N-terminus of UBI 29-41 during solid phase synthesis, with (99m)Tc-UBI 29-41. Methods were as follows: UBI 29-41 and HYNIC- or N(2)S(2)-conjugated peptide were labeled with technetium-99m.

Synthesis and characterization of rhenium(V) oxo complexes with N-[N-(3-diphenylphosphinopropionyl)glycyl]cysteine methyl ester. X-ray crystal structure of (ReO[Ph(2)P(CH(2))(2)C(O)-Gly-Cys-OMe(P,N,N,S)]).

The PN(2)S chelate N-[N-(3-diphenylphosphinopropionyl)glycyl]-S-tritylcysteine methyl ester [PN(2)S(Trt)-OMe] was synthesized and reacted with ReOCl(3)(PPh(3))(2) and Ph(4)P[ReOCl(4)]. The reactions of both tritylated and detritylated ligands with Re(V)O precursors gave two diastereomers, 9a and 9b, of the ReO(PN(2)S-OMe) complex. The two isomers, produced in a 1:1 molar ratio, are stable and do not interconvert.

CCK8 peptide derivatized with diphenylphosphine for rhenium labelling: synthesis and molecular mechanics calculations.

A novel CCK8 derivative bearing a chelating agent at its N- end and its oxo-rhenium(V) complex have been synthesized and characterized. The chelating agent N-[N-13-(diphenylphosphino)propionyl]glycyl]cysteine (PN2S) ligand, the coordination set of which is made by the phosphorus atom of phosphine, the nitrogen atoms of the two amido groups and the sulphur atom of cysteine, has been used due to its high affinity towards the oxo-rhenium(V) moiety. Molecular modelling studies indicate that the CCK8 peptide adopts the right conformation for cholecystokinin receptor binding, and that modifications on the N-terminal side of CCK8 obtained by introducing chelating agents and its metal complexes should not affect the interaction with CCK(A) receptor.