A comparative study of manganese meso-sulfonatophenyl porphyrins: contrast-enhancing agents for tumors.

Four manganese meso-sulfonatophenyl porphyrins were prepared, characterized and investigated for their potential as tumor-specific MRI contrast-enhancing agents in mice bearing subcutaneous implants of a mammary carcinoma (SMT-F). The trisulfonated tetraphenyl porphyrin, MnTPPS3 presented the most favorable profile: bio-distribution, tumor concentration and tumor relaxivity, when compared at 24 hr postinjection. Imaging experiments revealed that a time-dependent delineation of tumor morphology occurs in response to MnTPPS3 that appears to correlate with necrotic regions of the tumor.