TY - JOUR T1 - Formulation of <sup>18</sup>F-FDG: pH Adjustment of Buffered Solution JF - Journal of Nuclear Medicine Technology JO - J. Nucl. Med. Technol. SP - 48 LP - 49 DO - 10.2967/jnmt.111.092825 VL - 40 IS - 1 AU - Teresa Martinez AU - Luis Leiva Y1 - 2012/03/01 UR - http://tech.snmjournals.org/content/40/1/48.abstract N2 - 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. ER -