Biodegradable microspheres are prepared by dispersing an anticancer agent in an organic solvent with vigorous stirring, addi polymer, mixing with an aqueous phase to form an emulsion. The organic solvent is extracted by addition of water and the suspens of microspheres is filtered off. Biodegradable microspheres are prepared by dispersing an anticancer agent in an organic solvent with vigorous stirring, add a polymer, mixing with an aqueous phase to form an emulsion. The organic solvent is extracted by addition of water and the suspens of microspheres is filtered off. The organic solvent used is preferably dichloromethane, and the mixing is effected at around 2 degrees C. The polymer is preferably poly(d,l-lactic acid/glycolic acid), (PLAGA) equal quantities of the two acids being used i the copolymerization. The anticancer agent is hydrophilic and /or does not cross the blood brain barrier. It may be a 5-fluorour (5-FU), platinum derivatives, taxanes, gemcitabine, VP16, mitomycin, idoxuridine, topoisomerase 1 inhibitors, nitroso ureas, methotrexate, bleomycin, adriamycin, cytoxan, vincristin, and immunomodulating cytokins. Independent claims cover the use of these suspensions as medicines to be used simultaneously, sequentially, or separately t radiotherapy to treat glioblastomas, the microspheres being injected into the into the parenchymatous space and increasing the l span of the patient by at least 90 weeks, preferably at least 160 weeks.
