Eluent solution

Abstract

The present invention provides a novel method for the preparation of 18 F-fluoride ( 18 F) for use in radiofluorination reactions. The method of the invention finds use especially in the preparation of 18 F-labelled positron emission tomography (PET) tracers. The method of the invention is particularly advantageous where bulk solutions are prepared and stored in prefilled vials rather than being freshly prepared on the day of synthesis. Also provided by the present invention is a radiofluorination reaction which comprises the method of the invention, as well as a cassette for use in carrying out the method of the invention and/or the radiofluorination method of the invention on an automated radiosynthesis apparatus.

1 - 19 . (canceled) 
     
     
         20 . A cassette for carrying out the radiofluorination reaction comprising:
 (i) an anion exchange column suitable for trapping an aqueous solution of  18 F;   (ii) a first vial containing an eluent solution, wherein the eluent solution comprises a mixture of potassium carbonate and kryptofix in an aqueous alkanol solvent and being devoid of acetonitrile; and   (iii) a second vial containing a precursor compound which upon reaction with  18 F— results in an  18 F-labelled PET tracer;   wherein said eluent solution is capable of being (i) prepared in bulk and (ii) stored in the first vial prior to use, thereby affording a consistent percentage radiochemical yield of the  18 F-labelled PET tracer.   
     
     
         21 . The cassette as defined in  claim 20  which further comprises one or more of:
 (iv) drying means; 
 (v) an ion exchange cartridge for removal of excess  18 F—; 
 (vi) a cartridge for removing any protecting groups; and, 
 (vii) one or more solid-phase extraction cartridges to obtain said  18 F-labelled PET tracer in a purified form. 
 
     
     
         22 . The cassette as defined in  claim 20  wherein said anion exchange column is an anion exchange column. 
     
     
         23 . The cassette as defined in  claim 20  wherein said anion exchange column is a quaternary methylammonium (QMA) column. 
     
     
         24 . The cassette as defined in  claim 20  which is automated. 
     
     
         25 . The cassette as defined in  claim 20 , wherein the cassette is suitable for use with an automated radiosynthesis apparatus. 
     
     
         26 . The cassette as defined in  claim 20 , wherein said  18 F-labelled PET tracer is 2-deoxy-2-[ 18 F]fluoro-D-glucose, [ 18 F] fluorothymidine, [ 18 F] fluoronitroimidazole, 6-[ 18 F]fluoroDOPA, [ 18 F]setoperone, [ 18 F]altanserin, [ 18 F]N-methylspiperone, 6-[ 18 F] fluorodopamine, (−)6-[ 18 F]fluoro-norepinephrine, I6α-[ 18 F]fluoroestradiol, [ 18 F]fleroxacin or [ 18 F]fluconazole. 
     
     
         27 . The cassette as defined in  claim 25 , wherein said  18 F-labelled PET tracer 1s 2-deoxy-2-[ 18 F]fluoro-D-glucose, [ 18 F]fluorothymidine or [ 18 F]fluoronitroimidazole. 
     
     
         28 . The cassette as defined in  claim 25 , wherein the  18 F -labelled PET tracer is [ 18 F]FDG or [ 18 F]FACBC.