Table 4.

Kinetic inertness data for GBCAs and Mn²⁺ complexes recorded under different experimental conditions. Dissociation Challenge 1: 2.5 mM contrast agent is incubated with 2.5 mM Zn²⁺ in 50 mM pH 7.0 phosphate buffer at 37 °C, and kinetic inertness is compared by measuring the time required to achieve 20% release of the paramagnetic ion (t_20%). Dissociation Challenge 2: 1 mM contrast agent, 25 mM Zn²⁺, pH 6.0 MES buffer. Dissociation Challenge 3. [contrast agents] = [Zn²⁺ or Cu²⁺] = 0.01 mM, pH 7.4,. Dissociation Challenge 4. [contrast agents] = [Zn²⁺ or Cu²⁺] = 1.0 mM.

	t_20% Zn²⁺ challenge 1 (h)	t_1/2 Zn²⁺ challenge 2 (h)	t_1/2 Zn²⁺ challenge 3 (h)	t_1/2 Zn²⁺ challenge 4 (h)
Gd-DTPA	4.4,²⁴² 2.8⁷⁹	0.013⁷⁹	330 ^{a, 85}	3.5 ^{a, 85}
Gd-DTPA-BMA	1.0²⁴²
Gd-BOPTA	10²⁴²
Gd-EOB-DTPA	25²⁴²
MS-325	60²⁴²
Gd-DOTA	>83²⁴²		3.8×10^{5 a, 76}	3.8×10^{5 a, 76}
Gd-HP-DO3A	>80²⁴²
Gd-DO3A-butrol	>80²⁴²
Mn-EDTA			.076^{a, 114}	4.3*10^{−3a, 114}
Mn-CyDTA		0.18⁷⁹	12^{a, 114}	12^{a, 114}
Mn-PhCDTA			19^{a, 243}	0.86^{a, 243}
Mn-PyC3A	1.8⁷⁹	0.29⁷⁹
Mn-12-PyN4A			2.6^{a, 83}	2.6^{a, 83}
Mn-15-PyN5			11^{a, 84}	11^{a, 84}
Mn-PC2A-EA		54⁷⁸	8100^{a, 78}	8100^{a, 78}
Mn-1,4-DO2A			49^{a, 77}	49^{a, 77}
Mn-1,7-DO2A			58^{a, 77}	58^{a, 77}
Mn-1,4-DO2AM			560^{a, 77}	560^{a, 77}

Denotes t_1/2 estimated from empirical rate law data.