A pharmaceutically acceptable solubilizing composition comprising (i) at least one tocopheryl compound having a polyalkylene glycol moiety and (ii) at least one alkylene glycol fatty acid monoester or mixture of alkylene glycol fatty acid mono- and diester is disclosed. The solubilizing composition is useful in the manufacture of a pharmaceutical dosage form which comprises a melt-processed mixture of at least one active ingredient, at least one pharmaceutically acceptable polymer. The active ingredient(s) may be inhibitors of HIV protease. The solubilizing composition enhances the bioavailability of the active ingredient after oral intake.