Abstract
The binding of 5-ftuorouracil to polybutylcyanoacrylate nanoparticles yielded an enhanced efficacy against Crocker sarcoma S 180 and a higher toxicity of the drug measured by induced leukopenia, body weight loss and premature death. The efficacy was further increased by an increase in the polymer-to-drug ratio. The nanoparticles yielded a prolonged persistence of the 5-fluorouracil in all organs examined including the tumor. These particles hold promise as carriers for cytostatics, since their distribution may be favorably altered by coating them with certain proteins or surfactants or by the attachment of monoclonal antibodies.