Table 1.

Quality control parameters of the final [¹¹C]tozadenant tracer formulation.

Parameter	Method	Unit	Specification	Result
Appearance	visually	-	clear, no particles	conform
Activity concentration at EOS	calculated	MBq/mL	≥30	172 ± 95
Radiochemical identity	HPLC	%	±5	0 ± 2
Radiochemical purity	HPLC	%	≥90	95.0 ± 2.8
Carrier identity	HPLC	%	±5	0 ± 2
Carrier concentration	HPLC	µg/mL	≤5.0	1.12 ± 0.48
Total concentration of unknown impurities a	HPLC	µg/mL	≤5.0	0.16 ± 0.16
Methanol concentration	GC	mg/mL	≤1.0	0.06 ± 0.03
Ethanol concentration	GC	%vol	≤10	9.10 ± 0.49
Acetone concentration	GC	mg/mL	≤1.0	n.d.
Acetonitrile concentration	GC	mg/mL	≤0.41	n.d.
DMSO concentration	GC	mg/mL	≤1.0	n.d.
DMA concentration	GC	mg/mL	≤1.0	n.d.
pH	indicator	-	4.5–8.5	5.3 ± 0.6

^a Based on the molecular weight and extinction coefficient of tozadenant.