A method for preparing biodegradable microspheres containing an anticancer agent selected from the group comprising 5-fluorour (5-FU), platins such as carboplatin and cisplat taxanes such as docetaxel and paclitaxel, gemcitabine, VP16, mitomycin, idoxuridine, 1 inhibitors such as irinotecan, topotecan and camptothecins, nitrosou such as BCNU, ACNU or MCNU, methotrexate, bleomyci, adriamycin, Cytoxan and vincristine, immunomodula ing cytokines such as IL2, IL6, IL12 and IL13 and interfons, coated with a polymer selected from the group consisting of ethylcellulose, polystyrene, poly(e-capro actone), poly(d, 1-lactic acid) and poly(d,l-lactic acid-co-glycolic acid), by emulsification-extraction which consists in dispersing the polymer and the anticancer agent in dichloromethane, said anticancer agent being ground before dispersed in dichloromethane, such that the size of the crystals of the anticancer agent is between 15 and 50 µm, in mixing the organic phase obtained with an aqueous phase at approximately 2°C so to obtain an emulsion, in extracting the dichloromene by adding water at 4°C and then in filtering the suspension of microspheres obtained, characterised that the anticancer agent is dispersed in dichloromethane with vigorous stirring, before the polymer is added.
