Retard form of pharmaceuticals with insoluble porous diffusion coatings

摘要

A pharmaceutical dosage unit retard form having a constant, pH-independent release rate of active ingredient, consisting of a core comprising an active ingredient, and a semi-permeable diffusion coating over the core, where the coating consists of a water-insoluble film-former, a water-soluble polymer and eventually an acid-insoluble polymer incorporated therein.