Purified hematoporphyrin derivative for diagnosis and treatment of tumors, and method.

A method of synthesizing and purifying a high molecular weight aggregate, derived from hematoporphyrin, said material being useful in the localization and treatment of tumors. The substance results from the hydrolysis of the reaction mixture of hematoporphyrin and acetic-sulfuric acids. The material is purified by cycling the crude product through a micro-porous membrane system in which exclusion of low molecular weight by-products is effected. The substance is tumor-selective and photosensitizing. It is retained in tumors longer than in normal tissues and fluoresces red to aid in diagnosis. Strong illumination of tumors retaining the substance results in necrosis, while normal tissues which have generally eliminated the drug remain unaffected. The high molecular weight aggregate has an empirical formula of approximately C68H70N8O11 (Na plus H)4.