Inclusion Complexes of Racemic Ibuproxam and of Optically Active Ibuproxam with Cyclodextrin Derivatives, Process for the Preparation Thereof, Pharmaceutical Preparations Containing these Inclusion Complexes or Containing Optically Active S-(+)-Ibuproxam, and Use Thereof There are disclosed novel inclusion complexes of racemic ibuproxam and of optically active S-(+)-ibuproxam with hydrophilic and hydrophobic cyclodextrin derivatives and, in the case of optically active S-(+)-ibuproxam, also with .beta.-cyclodextrin alone. Further a process for preparing S-(+)-ibuproxam and inclusion complexes of racemic ibuproxam and of optically active S-(+)-ibuproxam with hydrophilic and hydrophobic derivatives of .beta.-cyclodextrin and, in the case of optically active S-(+)-ibuproxam, also with .beta.-cyclodextrin alone, is disclosed. Disclosed are also pharmaceutical compositions containing these inclusion complexes or optically active S-(+)-ibuproxam. Optically active S-(+)-ibuproxam and novel inclusion complexes of racemic ibuproxam and of optically active ibuproxam with cyclodextrin derivatives and, in the case of optically active S-(+)-ibuproxam, also with .beta.-cyclodextrin alone, are better soluble in water and have improved biopharmaceutical properties such as lesser toxicity, better antiinflammatory action and non-irritation of the gastric mucous membrane.