No abstract

decaene (30), respectively, are reported. Single crystals suitable for X-ray diffraction were obtained for the La(III) complex 3, the Gd(III) complexes 9 and 37, the Eu(III) complex 36, and the Lu(III) complex 22, by dissolving the respective complex in MeOH/CHC^a nd layering with diethyl ether. The five lanthanide(lll) texaphyrin complexes all crystallize in the triclinic space group, P\ (No. 2), with Z = 2. The final R's, for data collected at reduced temperatures (<-90 °C), were 0.

Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.

Cancer and cardiovascular disease are the leading causes of death in the western world. Photodynamic therapy (PDT) has demonstrated activity in the treatment of superficial cancerous lesions and as an intraoperative adjunct during surgical debulking. Texaphyrins are pure, synthetic water-soluble macrocycles that localize in both cancerous lesions and atheromatous plaque. Lutetium texaphyrin (PCI-0123) is activated by tissue-penetrating far red light (720-760 nm). Patient diagnosis and treatment planning is possible via magnetic resonance imaging (MRI) with the paramagnetic gadolinium texaphyrin (PCI-0120) or via fluorescence imaging using the diamagnetic PCI-0123. In this study it is shown that texaphyrins localize selectively in cancer and atheromatous plaque. PDT with PCI-0123 is found to cause selective photodamage to the diseased tissue. Specifically, PCI-0123 acts to eradicate the SMT-F murine mammary tumors and diet-induced atheromatous plaque in rabbits.

Magnetic resonance imaging (MRI) is now well established as an important tool for the diagnosis and evaluation of a variety of diseases.* 1 2345Nonetheless, considerable effort continues to be devoted to the development and study of potential MRI contrast