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