The invention relates to an active substance (W) for using in a method for releasing active substances (W), in which a moulded body (F) containing a composition (Z) comprising a silicone-containing polymer (P) and an active substance (W) is mixed with water, whereby the composition (Z) releases an active substance (W), the silicone-containing polymer (P) containing at least one siloxane unit of general formula I and no, or at least one unit of general formula II R1b(X)cSiO[4-(b+c)]/2 (I), R2aSiO(4-a)/2 (II), in which R1, R2, X, a, b and c d have the designations defined in claim 1. The invention also relates to the moulded body (F), and to a method for producing the moulded body (F), in which a solution of the silicone-containing polymer (P) is mixed with the active substance (W) and the mixture thus created is evaporated.
