Stabilization of the pharmaceutical active solid substance atorvastatin alone or in a mixture with other solid substances embedded in a gaseous mixture is carried out in such a manner that in the surrounding gaseous mixture a partial pressure of oxygen of at most 2 kPa, preferably less than 1 kPa, more preferably less than 0.4 kPa is maintained. The corresponding partial pressure is achieved either by use of oxygen absorbers, by packaging under a pressure of 0.3 - 10 kPa, or by packaging under a slight overpressure of an inert gas, preferably nitrogen, the gas being introduced, by means of nozzles, into the cavities, optionally also into the space of the press roller and of the wiper station.