The invention relates to a partly neutralized anionic (meth)acrylate copolymer consisting of radically polymerized units containing 25-95% by weight (meth)acrylic acid C1 to C4 alkylesters and 5-75% by weight (meth)acrylate monomer with an anionic group, wherein 0.1 to 25% contained anionic groups are neutralized by a base. Said invention is characterized in that said base is embodied in the form of an cationic organic base whose molecular weight is greater than 150. A medical form containing said partly neutralized anionic (meth)acrylate copolymer and the use of said partly neutralized anionic (meth)acrylate copolymer for producing a medical form rapidly releasing an active substance having a determined pH value are also disclosed.