This work describes a new approach to prepare solvent-free solid dispersions (SDs) for Nimesulide (NMS), involving the use of microwaves irradiation (MW). In particular, the microwave technology has been considered in order to prepare an enhanced release dosage form for the poorly soluble drug Nimesulide (NMS), employing Gelucire (R) 50/13 and Poloxamer 188 (Lutrol (R) F 68) as surfactant carriers. Their physicochemical characteristics and dissolution properties were compared to the corresponding physical mixtures and the drug alone. The results attested a correspondence of the solid state of the drug before and after the irradiation treatment and that an amorphisation form of the drug in SD systems was obtained. After six months this data was confirmed. These results, together with the presence of the selected carriers, determined a remarkable enhancement of solubility and an in vitro dissolution rate of the drug suggesting that the microwave technique could be considered as a new and interesting method to prepare drug-polymer systems. (c) 2009 Elsevier B.V. All rights reserved.