Texaphyrin gadolinium chelate

Figure 1.17 The texaphyrin-gadolinium chelate structure used as a photosensitizer and MRI contrast agent in the detection and treatment of cancer.

Another approach has been tackled with by Sessler et al. [37, 38] who described gadolinium(III) complexes with texaphyrins as potential MRI contrast agents. When the expanded porphyrin ring is subtituted by water solubilizing groups (Fig. 5), the chelate is sufficiently water soluble to be injected. It is... 

In accord with this expectation, a first-generation water-soluble texaphyrin 10.1 (Figure 10.1.2) was found to show an exceptionally high relaxivity in aqueous medium (/ i = 16.9 1.5 mM s 50 MHz room temperature).At the time it was obtained, this important result was considered to augur well for the in vivo usefulness of 10.1 it meant that high efficacy could be expected at doses considerably lower than those required for more conventional, carboxylate-derived gadolinium(III) chelates. 

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