. Author manuscript; available in PMC: 2021 Jul 21.

Published in final edited form as: Inorg Chem. 2020 Jul 28;59(16):11715–11727. doi: 10.1021/acs.inorgchem.0c01629

Table 3.

Results from in vitro EDTA transchelation stability assays.^*

Starting complex	Ligand challenge	pH	% Intact starting species by incubation time
Starting complex	Ligand challenge	pH	Initial	1 h	3 h	1 d	3 d	5 d	7 d
⁸⁹Zr(DFO2)	100 fold excess EDTA	8.0	100	100	100	99.9 ± 0.1	94.3 ± 2.2	88.6 ± 2.8	81.4 ± 1.4
		7.5	100	100	100	100	98.9 ± 1.0	97.6 ± 1.2	95.0 ± 0.5
		7.0	100	100	100	99.8 ± 0.1	98.7 ± 0.3	92.5 ± 6.4	85.3 ± 2.7
		6.5	100	100	99.5 ± 0.2	99.9 ± 0.2	98.0 ± 1.5	95.5 ± 1.9	90.4 ± 4.9
		6	100	98.6 ± 0.4	96.6 ± 0.7	77.6 ± 2.9	42.1 ± 8.0	27.1 ± 8.1	20.6 ± 5.9
		5.5	100	95.6 ± 1.0	90.2 ± 0.5	35.4 ± 1.1	7.0 ± 2.0	3.9 ± 1.8	1.5 ± 0.7
		5.0	100	74.3 ± 0.9	43.9 ± 3.0	1.6 ± 0.1	1.0 ± 0.4	1.0 ± 0.6	0.6 ± 0.2
⁸⁹Zr(DFO)	100 fold excess EDTA	8.0	98.1 ± 0.2	96.8 ± 1.3	97.5 ± 0.4	91.8 ± 1.3	75.9 ± 1.7	53.7 ± 1.4	33.6 ± 4.3
		7.5	97.3 ± 0.6	96.6 ± 0.3	95.8 ± 0.5	84.9 ± 2.1	59.7 ± 5.5	36.5 ± 11.2	23.7 ± 9.6
		7.0	96.2 ± 0.7	95.9 ± 0.7	95.5 ± 0.7	79.0 ± 1.6	50.2 ± 3.6	28.1 ± 8.1	16.1 ± 4.4
		6.5	95.5 + 0.9	96.4 + 2.2	92.7 + 0.4	58.2 ± 3.6	21.6 + 1.5	11.6 + 0.7	8.5 + 1.4
		6	99.3 + 0.2	94.9 + 0.2	84.6 + 2.2	20.4 ± 1.5	4.5 + 0.2	3.6 + 0.5	3.4 + 1.3
		5.5	99.1 ± 0.2	89.6 ± 0.7	69.9 ± 1.5	5.3 ± 0.8	2.4 ± 0.3	2.7 ± 0.3	1.9 ± 0.1
		5.0	97.0 ± 0.2	63.5 ± 1.3	27.3 ± 3.3	1.9 ± 0.7	1.1 ± 0.1	1.2 ± 0.1	1.1 + 0.0

			100–99%	98–90%	89–80%	≤ 79%

Pre-radiolabeled [⁸⁹Zr]Zr(DFO) and [⁸⁹Zr]Zr(DFO2) complexes were mixed with a 100-fold molar excess of EDTA chelator at various pH values, and monitored by radio-iTLC for 7 days.