A method to detect leakage of water-soluble intercapling the active substance to a species capable of interlators such as ethidium bromide and propidium iodide calating with DNA. This approach is explored, for exfrom lipomes (egg-lecithin and egg-lecithin/cholesample, in the search for effective substances to be used terol) by means of fluorescence is presented. The addiin boron neutron capture therapy (BNCT) 2 (4). Recent tion of excess DNA outside the liposomes brings about investigations show that small unilamellar vesicles intercalation of released dye with the DNA. The inmay successfully deliver therapeutic amounts of both crease in fluorescence intensity that results from the water-soluble and lipophilic boron-rich compounds to dye-DNA complex is used to detect the degree of dye tumors (5). To avoid rapid clearance from the tumor release. Titration and surfactant-induced leakage mass, pilot studies using boron-containing species measurements display the suitability of the method. linked to DNA intercalators, such as carboranyl phe-Spontaneous leakage measurements show that propidnanthridinium analogs, have been initiated (4). The ium has much lower leaking rates than those of ethidresults from this study indicate that although the inium. This is probably due to the less lipophilicity of vestigated boronated phenanthridinium analogs pospropidium as estimated from the partition coefficients sess DNA binding potential, a substantial amount of between octanol and medium. Stabilizing the egg-lecithe boron-rich compounds end up in the cell membrane.