new solid drug dispersions are described in which the drug is present in amorphous form and massively dispersed inside the particles of an organic carrier selected from cross - linked polymers and / or a complexing agents . these dispersions are obtainable by mixing together the drug and the carrier and applying an oscillating electromagnetic field to the mixture , to a frequency belonging to the microwave region ; the microwaves are applied according to a specific heating cycle wherein the drug - carrier mixture is heated at a temperature higher than the melting point of the drug for at least 5 minutes . with respect to the known techniques , the present invention allows to increase in the amount of drug incorporated into the carrier in amorphous form , and to increase the physical stability of the amorphous phase . this is particularly useful in the preparation of pharmaceutical compositions based on drugs which are crystalline in nature , such as are notoriously sparingly soluble in water : thanks to the increased amounts and stability of the drug in amorphous form , the resulting formulations have a more rapid and intense effect , and are endowed with greater bioavailability .