A coating material, containing a mixture of i) a polymer obtained by radical polymerization from a) N,N-diethylaminoethyl methacrylate, and b) at least one radically polymerizable compound, selected from esters of α,β-ethylenically unsaturated mono- and dicarboxylic acids with C1-C18 alkanols, as component A, ii) one or more antioxidants as component B, iii) one or more plasticizers as component C, and iv) other excipients as components D, wherein the total amount of the mixture of components A-D is 100 wt. %.