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|Title:||Methods for treatment of tumors|
|Abstract:||To obtain tumor-selective, photosensitizing drugs useful in the localization of neoplastic tissue and treatment of abnormal neoplastic tissue such as tumors, one of two methods is used. In the first method, a hydrolyzed mixture of the products of reaction of hematoporphyrin with acetic acid and sulfuric acid is cycled through a microporous membrane system to exclude low molecular weight products. In the second method, drugs are synthesized or derived from other pyrrole compounds. The drugs: (1) include two covalently bound groups, each with four rings, some of which are pyrroles such as phlorins, porphyrins, chlorins, substituted pyrroles, substituted chlorins or substituted phlorins, each group being arranged in a ring structure, connected covalently to another group and have a triplet energy state above 37.5 kilocalories per mole; (2) are soluble in water, forming an aggregate of over 10,000 molecular weight in water and have an affinity for each other compared to serum protein such that 10 to 100 percent remain self aggregated in serum protein; and (3) are lipophillic and able to disaggregate and attach to cell plasma, nuclear membrane, mitochondria, lysosomes and tissue. The drug obtained by the first method has an empirical formula of approximately C.sub.68 H.sub.70 N.sub.8 O.sub.11 or C.sub.68 H.sub.66 N.sub.8 O.sub.11 Na.sub.4. Neoplastic tissue retains the drug after it has cleared normal tissues and illumination results in necrosis. Moreover, other photosensitizing materials may be combined with a carrier that enters undesirable tissues and cells of the reticular endothelial system such as macrophages. These photosensitizing materials: (1) must have a triplet energy state above 3.5 kilocalories per mole; (2) cannot be easily oxidized; and (3) not physically quench any required energy state. Preferably, this photosensitizing material should be lipophilic.|
|Inventor(s):||Dougherty; Thomas J. (Grand Island, NY), Potter; William R. (Grand Island, NY), Weishaupt; Kenneth R. (Sloan, NY)|
|Assignee:||Health Research, Inc. (Buffalo, NY)|
1. A process for the in vivo destruction of tumors in a host comprising the steps of:
injecting into said host a composition comprising porphyrin aggregates which are fluorescent, photosensitizing and capable of localizing in and being retained in tumor cells for a longer time than in normal tissues, which composition is prepared by a process which comprises raising the pH of a hematoporphyrin derivative preparation in aqueous medium to 6.5-2 to obtain said porphyrin aggregates of 10 kd or greater; and
separating said aggregates from the remainder of the hematoporphyrin derivative preparation to obtain said composition;
wherein said hematoporphyrin derivative preparation has been prepared by treating hematoporphyrin hydrochloride with a mixture of acetic acid and sulfuric acid;
waiting for a predetermined period of time; and
illuminating the tumor tissue with light at a predetermined intensity.
2. The process of claim 1 wherein said composition is used in a dosage of from about 1 to 4 mg/kg of body weight of the host.
3. The process of claim 1 wherein the time delay between the injection and illumination is within a range of about 3 hours to 7 days.
4. The process of claim 1 wherein said intensity of illumination is at least 5 mw/cm.sup.2.
5. The process of claim 1 wherein said illuminating step is conducted by transmitting radiation through a light conductor to a location adjacent to the tumor tissue and transmitting the radiation through a diffuser onto the tumor.
6. The process of claim 5 which further includes transmitting radiation from the tumor back to the source of radiation through a light conductor and using said radiation to control the dosage of radiation.
7. The process of claim 5 wherein transmitting radiation through a diffuser includes transmitting radiation through an air fill bulb whereby heat is dissipated.
8. The process of claim 4 wherein the intensity of illumination is between 0.5 w/cm.sup.2 and I kw/cm.sup.2, whereby thermal effects are obtained.
9. The process of claim 1, wherein said pH to which said hematoporphyrin derivative preparation in aqueous medium is raised is about 9.5.
10. The process of claim 1 wherein the separation is effected by filtering.
11. The process of claim 10 wherein the pH of 9.5 is maintained during filtration.