PT  - JOURNAL ARTICLE
AU  - Martinez, Teresa
AU  - Leiva, Luis
TI  - Formulation of <sup>18</sup>F-FDG: pH Adjustment of Buffered Solution
AID  - 10.2967/jnmt.111.092825
DP  - 2012 Mar 01
TA  - Journal of Nuclear Medicine Technology
PG  - 48--49
VI  - 40
IP  - 1
4099  - http://tech.snmjournals.org/content/40/1/48.short
4100  - http://tech.snmjournals.org/content/40/1/48.full
SO  - J. Nucl. Med. Technol.2012 Mar 01; 40
AB  - The steam-sterilized 18F-FDG of our laboratory frequently has a pH of around 6.5. To avoid decomposition, we studied the possibility of adjusting the pH by adding a pharmaceutical compound but without modifying the usual production sequence and reagents. Methods: Citric acid in 4 concentrations (0.01, 0.03, 0.05, and 0.06 M) was added to routine batches of 18F-FDG. Established pharmacopeia quality controls at 0 and 12 h after synthesis were run, and the dilution effect was checked. Results: A 0.06 M concentration of 1:15 v/v citric acid brought about a pH range of 5.46–5.68; did not change significantly after 1/10 dilution; and did not interfere with quality control. The results of quality control 12 h after dispensing were in the desired range. Conclusion: A 0.06 M concentration of 1:15 v/v citric acid modifies pH in a buffered 18F-FDG solution without the need to change the synthesizer protocol or reagent composition. This new formulation allows pH adjustment; is an easy, reliable, and safe method with no technical difficulties; and does not interfere with the quality of the radiopharmaceutical.