Description:SAME AS UPLOADED , Claims:1. An automated method to obtain a radiopharmaceutial composition of 18F-1-amino-3-fluoro-cyclobutane-1-carboxylic acid (18F-FACBC) wherein said composition;
(a) comprises 50-100 mM citrate buffer; and,
(b) has a pH of 4.0 - 5.0;
wherein said method comprises:
(i) reacting with a suitable source of [18F]fluoride a precursor compound of Formula I:

wherein:
LG is a leaving group;
PG1 is a carboxy protecting group; and,
PG2 is an amine protecting group;
to obtain a compound of Formula II:

wherein PG1 and PG2 are as defined for Formula I;
(ii) reacting said compound of Formula II with a PG1 deprotecting agent to obtain a compound of Formula III:

wherein PG2 is as defined for Formula I;
(iii) reacting said compound of Formula III with a PG2 deprotecting agent to obtain a crude product containing 18F-FACBC;
(iv) carrying out a purification step comprising passing said crude product through a hydrophilic lipophilic balanced (HLB) solid phase to obtain [18F]-FACBC, wherein said crude product is not passed through an ion retardation column; and
(v) formulating said [18F]-FACBC with citrate buffer to obtain said pharmaceutical composition.
2. The method as defined in Claim 1 wherein said [18F]-FACBC is trans-1-amino-3-[18F]-fluorocyclobutanecarboxylic acid (anti-[18F]-FACBC):

said compound of Formula I is a compound of Formula Ia:

said compound of Formula II is a compound of Formula IIa:

and, said compound of Formula III is a compound of Formula IIIa:

wherein PG1 and PG2 are as defined in Claim 1 for Formula I.
3. The method as defined in any one of Claims 1-2 wherein the pharmaceutical composition comprises 60-90 mM citrate buffer.
4. The method as defined in any one of Claims 1-3 wherein the pharmaceutical composition has a pH of 4.1-4.5.
5. The method as defined in any one of Claims 1-4 wherein the pharmaceutical composition has an end of synthesis (EOS) radioactive concentration (RAC) of at least 1000 MBq/mL.
6. The method as defined in any one of Claims 1-5 wherein the pharmaceutical composition comprises not more than 150 µg/mL 1-amino-3-hydroxyl-cyclobutane-1-carboxylic acid (hydroxyl-ACBC).
7. The method as defined in any one of Claims 1-6 wherein the pharmaceutical composition comprises not more than 0.15 µg/mL 1-amino-3-fluoro-cyclobutane-1-carboxylic acid (FACBC).
8. The method as defined in any one of Claims 1-7 wherein the pharmaceutical composition comprises not more than 2.0 µg/mL 1-amino-3-chloro-cyclobutane-1-carboxylic acid (chloro-ACBC).
9. The method as defined in any one of Claims 1-8 wherein the pharmaceutical composition does not comprise a radiostabiliser.
10. The method as defined in any one of claims 1-9 which is carried out on an automated synthesis apparatus.
11. The method as defined in any one of Claims 1-10 wherein said PG1 deprotecting agent is NaOH.
12. The method as defined in any one of Claims 1-11 wherein said PG2 deprotecting agent is HCl.