The present invention relates to a batch method for impregnating a nonporous polymer pharmaceutical carrier with an active substance, characterised in that said method includes the following consecutive steps: a) mixing the active substance and the nonporous polymer pharmaceutical carrier, the pharmaceutical carrier being in a solid form and insoluble in supercritical CO2 and not being non-crosslinked polyvinylpyrrolidone； b) performing a step of molecular diffusion in the absence of water by contacting, in a static mode without agitation, the mixture obtained in step a) with supercritical CO2 at a pressure of 80 to 170 bars, at a temperature of 31 to 90° C. for 1 to 6 hours； c) recovering the polymer pharmaceutical carrier impregnated with the active substance obtained in step b), the impregnated pharmaceutical carrier being nonporous and being in a solid form and the active substance being in an amorphous form, the method being implemented in the absence of an additional solvent. The invention further relates to a polymer pharmaceutical carrier in a nonporous solid form impregnated with an active substance characterised in that said carrier can be obtained by the method according to the present invention, in that the active substance is in an amorphous form and is water-soluble, and in that the polymer pharmaceutical carrier is not non-crosslinked polyvinylpyrrolidone and is insoluble in supercritical CO2.
