The invention relates to dosage forms which contain preparations of poorly water-soluble substances in a polymer matrix of polyether copolymers, said polyether copolymers being obtained by the radically initiated polymerization of a mixture from 30 to 80% by weight of N-vinyl lactam, 10 to 50% by weight of vinyl acetate and 10 to 50% by weight of a polyether, and at least one poorly water-soluble polymer, the poorly water-soluble substance being present in the polymer matrix as an amorphous substance.