Table 3. Maximum Ionic Relaxivity for Gd-C4-IA and the Gd-C4-Protein Conjugates.

sample name	Max r1,ionic at 25 °C	Max r1,ionic at 37 °C
Gd-C4-IAa,c	10	7.5
Gd-C4-IAb,c	10	7.5
Gd-AaLS-13a,d	35	27.5
Gd-OP-3intCb,d	48	40
Gd-OP-2intCb,d	37.5	30
Gd-OP-1intCb,d	32.5	28
Gd-OP-1extCb,d	20	15

^aRelaxivity data in 50 mM sodium phosphate (pH 8.0), 200 mM NaCl, 5 mM EDTA.

^bRelaxivity data in 25 mM Tris (pH 7.6), 200 mM NaCl, 5 mM EDTA.

^cRelaxivity values at <0.02 T.

^dRelaxivity values at 0.5 T.