Method for labeling of sensitive and thermosensitive targeting biomolecules with technetium based compounds

Abstract

The present invention relates to a labeling procedure for the incorporation, in mild reaction conditions, of sensitive and thermosensitive targeting molecules into a [ 99m Tc(N)(PNP)]-based compound suitable for a kit formulation.

1 .- 50 . (canceled) 
     
     
         51 . A compound of formula (I) 
       
         
           
           
               
               
           
         
         wherein: 
         Tc is  99m Tc; 
         R is hydrogen (—H) or a group of formula —(CH 2 ) n -A, wherein n is an integer of 1 or 2 and A is selected from the group consisting of hydrogen (—H), hydroxyl (—OH), methyl (—CH 3 ), carboxyl (—COOH), sodium carbonyl (—COONa), amino (—NH 2 ), cyanide (—CN), sulfonyl (—SO 3 H) and sodium sulfonyl (—SO 3 Na); 
         R 1  is a group of formula —(CH 2 ) m —R 2 , wherein m is an integer of 1 to 6 and R 2  is selected from the group consisting of alkoxyl (—O-Ak), hydroxyl (—OH), carboxyl (—COOH), and amino (—NH 2 ); and 
         ZY is a bidentate ligand, coordinated with Tc through a combination of electron-donating atoms selected from the group consisting of [O − ,S − ], [S − ,S − ], [O − ,S], [O,S − ], [N,S − ], [N − ,S], and [N − ,S − ]; or a salt thereof. 
       
     
     
         52 . The compound according to  claim 51 , wherein R is selected from the group consisting of hydrogen (—H), methyl (—CH 3 ), hydroxymethyl (—CH 2 OH), ethyl (—CH 2 CH 3 ), and carboxyethyl (—CH 2 CH 2 COOH). 
     
     
         53 . The compound according to  claim 51 , having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         54 . The compound according to  claim 51 , having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         55 . The compound according to  claim 51 , having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         56 . The compound according to  claim 51 , having the formula: 
       
         
           
           
               
               
           
         
       
     
     
         57 . The compound according to  claim 51 , wherein ZY is coordinated with Tc through a combination of electron-donating atoms selected from the group consisting of [O − ,S − ], [N,S − ], [S − ,S − ], and [N − ,S], wherein ZY is not coordinated with Tc through [N,S − ] if R is —CH 3  and R 1  is —(CH 2 ) 2 —OCH 3 . 
     
     
         58 . The compound according to  claim 51 , wherein ZY is a cysteine, a cysteine derivative, or a dianionic form of a dithiolate derivative. 
     
     
         59 . The compound according to  claim 51 , wherein ZY is linked to, or is a part of a bioactive molecule and wherein the bioactive molecule is thermosensitive. 
     
     
         60 . The compound according to  claim 51 , wherein ZY is selected from the group consisting of Cys-cRGDfK, Biot-Abu-Cys and Glu-Urea-Lys-2-naphthyl-L-Ala-Amc-Cys. 
     
     
         61 . The compound according to  claim 51 , wherein the salt is HCL salt. 
     
     
         62 . The compound according to  claim 59 , wherein the bioactive molecule is selected from the group consisting of polypeptides, proteins, antibodies, and aptamers. 
     
     
         63 . The compound according to  claim 62 , wherein the antibodies comprise a Fab. 
     
     
         64 . A radiopharmaceutical composition suitable for protein-targeted SPECT imaging comprising the compound of formula (I), according to  claim 51 . 
     
     
         65 . The radiopharmaceutical composition according to  claim 64  further comprising one or more pharmaceutically acceptable carriers, diluents, or excipients. 
     
     
         66 . A process for preparation of a compound of formula (I) 
       
         
           
           
               
               
           
         
         wherein: 
         Tc is  99m Tc; 
         R is hydrogen (—H) or a group of formula —(CH 2 ) n -A, wherein n is an integer of 1 or 2 and A is selected from the group consisting of hydrogen (—H), hydroxyl (—OH), methyl (—CH 3 ), carboxyl (—COOH), sodium carboxyl (—COONa), amino (—NH 2 ), cyanide (—CN), sulfonyl (—SO 3 H) and sodium sulfonyl (—SO 3 Na); 
         R 1  is a group of formula —(CH 2 ) m —R 2 , wherein m is an integer of 1 to 6 and R 2  is selected from the group consisting of alkoxyl (—O-Ak), hydroxyl (—OH), carboxyl (—COOH), and amino (—NH 2 ); and 
         ZY is a bidentate ligand, coordinated with Tc through a combination of electron-donating atoms selected from the group consisting of [O − ,S − ], [S − ,S − ], [O − ,S], [O,S − ], [N,S − ], [N − ,S], and [N − ,S − ], wherein ZY is not coordinated with Tc through [N,S − ] if R is —CH 3  and R 1  is —(CH 2 ) 2 —OCH 3 , comprising: 
         reacting, at mild temperature and mild pH,  99m Tc-pertechnetate, a reducing agent, a nitrido nitrogen donor, and ZY with a bisphosphinoamine compound of formula (VII) 
       
       
         
           
           
               
               
           
         
         or formula (VIII) 
       
       
         
           
           
               
               
           
         
       
     
     
         67 . The process according to  claim 66 , comprising:
 a) mixing, at mild temperature,  99m Tc-pertechnetate, a reducing agent, and a nitrido nitrogen donor, to obtain a reactive  99m Tc-nitrido precursor [ 99m Tc≡N] int   2+ ; and   b) converting, at mild temperature and mild pH, the  99m Tc-nitrido precursor into a heterocomplex by addition of a buffer solution containing ZY and a bisphosphinoamine compound of formula (VII) or formula (VIII).   
     
     
         68 . The process according to  claim 66 , wherein the mild temperature is room temperature. 
     
     
         69 . The process according to  claim 66 , wherein the mild pH is about neutral pH. 
     
     
         70 . The process according to  claim 66 , wherein the mild temperature is room temperature and the mild pH is about neutral pH.