<p>Particle size has a significant impact on the dissolution kinetics of active pharmaceutical ingredients (API), which, together with poor water solubility, greatly limits their bioavailability. Rapid expansion of supercritical solutions (RESS) is a promising micronization method that can be used to obtain nanosized particles of APIs. RESS eliminates the occurrence of residual organic solvents in the final product by using carbon dioxide, but the limiting factors are the solubility of the API in supercritical carbon dioxide, crystallinity, and the need to control polymorphism. The creation of amorphous solid dispersions (ASDs), i.e., systems where the API molecules are dispersed in a polymer carrier, solves the problem of crystallinity inherent in RESS by inhibiting it due to the precipitation of the API with the polymer (sometimes in the presence of surfactants) from the solution or their joint remelting. The limitations of this approach are the need to control crystallinity during storage; the problem of the occurrence of residual solvents (in spray-drying, lyophilization and solvent-removal methods); and the use of a rather large amount of polymer, which complicates the identification of residual crystalline structures of the API. The combination of the RESS method with an ASD can produce an ASD without residual organic solvents, however, the API must dissolve in carbon dioxide, while the polymer becomes a liquid, transitioning into a rubber-like state. The present review is aimed at analyzing and systematizing data on the creation of ASDs by the RESS method with a description of the features of recrystallization and use of polymers.</p>