Biodistribution and toxicity of 2,4-divinyl-nido-o-carboranyldeuteroporphyrin IX in mice.

BALB/c mice with transplanted subcutaneous KHJJ mammary carcinomas were given 2,4-divinyl-nido-o-carboranyldeuteroporphyrin IX (VCDP), a prospective boron carrier for boron neutron-capture therapy, to determine the dose schedule that results in maximal boron uptake in tumor. A total dose of 270 +/- 10 micrograms/g body weight given in a 4-day multiple intraperitoneal injection schedule (3/day) resulted in 30-50 micrograms boron/g tumor. After such a dose, thrombocytopenia, granulocytosis and altered liver enzyme levels were measured in the blood. Blood boron clearance was followed for an 18 hr to 6 day post-injection period. Toxic effects of VCDP subsided within 4-6 days after the last injection. In view of the greater than 30 micrograms/g peak accumulation of boron in tumor from VCDP and the subsequent rapid reversal of VCDP toxicity, further studies of VCDP in small mammals relevant to its distribution, toxicity and potential clinical use for neutron-capture therapy of tumors appear warranted.