Novel Metalloporphyrins as Molecular MR Contrast Agents

Talaignair Venkatraman¹, Ines Batinic-Haberle², Vladimir Mouraviev², Haichen Wang², Chris lascola²

We have investigated a new class of therapeutic metalloporphyrins for their potential as molecular MR imaging probes for prostate cancer detection. Mn(III)TE-2-Pyp5+ (meso-tetrakis(N-ethyl-2-prydil)porphyrin) and Mn(III)TnHex-2-PYP5+ (meso-terakis(N-n-hexyl-2-pyridyl)porphyrin are powerful superoxide dismutase mimics with low toxicity and antineoplastic activity. In phantom experiments, we observe unusually high T1 relaxivity. In vivo, we observe selective accumulation of these probes in prostate tumor xenografts following a single dose of either compound. Relaxation changes in prostate tumors is 10-11 fold greater than in normal prostate gland, suggesting these compounds may be particularly effective at detecting multifocal disease in situ.