Formulation of 18F-FDG: pH Adjustment of Buffered Solution

Article Figures & Data

TABLE 1

pH of ¹⁸F-FDG with Citric Acid Added

Initial citric acid concentration (M)	Ratio of citric acid to ¹⁸F-FDG (v/v)	pH of ¹⁸F-FDG
Initial citric acid concentration (M)	Ratio of citric acid to ¹⁸F-FDG (v/v)	Batch 1	Batch 2	Batch 3
0	0	6.58	6.59	6.61
0.01	1:1	4.98	4.94	4.94
	1:15	6.27	6.25	6.26
	1:30	6.27	6.28	6.24
	1:60	6.29	6.28	6.29
0.03	1:1	3.91	3.90	3.91
	1:15	5.84	5.83	5.84
	1:30	5.89	5.90	5.88
	1:60	5.88	5.87	5.87
0.05	1:1	3.54	3.49	3.47
	1:15	5.70	5.71	5.66
	1:30	5.65	5.65	5.65
	1:60	5.62	5.65	5.65
0.06	1:1	3.36	3.33	3.32
	1:15	5.5	5.51	5.52
	1:30	5.58	5.57	5.58
	1:60	5.57	5.57	5.58

TABLE 2

Data of Formulation Tested in ¹⁸F-FDG Routine Production

	1:15 v/v citric acid:¹⁸F-FDG
Parameter	0.06 M	0.05 M	0.03 M
Number of batches studied	10	10	10
Radioactivity concentration of batches studied (MBq/mL)	2,600–4,000	2,600–4,000	2,600–4,000
pH range	5.46–5.68	5.51–6.22	5.68–6.52
¹⁸F-fluorodeoxymannose (median ± SD)	0.83% ± 0.73%	1.78% ± 0.81%	1.94% ± 0.81%
Pharmacopeia quality control	Passed	Passed	Passed
pH and radiochemical purity 12 h after synthesis	Passed	Passed	Passed