surface of the active ingredient or granules containing the active substance and the organic solvent is evaporated and thus the coating is stabilized and if desired a further layer containing another active ingredient is applied on the coating by known techniques by employing the coating of the invention a frame tablet of controlled release of active ingredients may also be prepared in this case the granulate containing the active ingredient is after coating the granulate with a coating according to the invention and after adding the usual additives compressed into tablets thus the coating on the surface of granules deformed during the pressing is partially torn on pressure and a bond is formed at the coating interface thus a frame structure is formed from the coating and the active ingredient releases slowly from the cavities of the frame structure 100 g of cellulose triacetate are dissolved in 1200 ml of dichloromethane to this solution 20 g of polyethyleneglycol of an average molecular weight of 6000 in 80 ml of water is added whereafter the aqueous solution is dispersed at 20 u00b0 c in a colloid mill to an emulsified phase of particles of a diameter of 1 to 5 micron the thus prepared varnish solution is used as a coating and in an air current at 40 u00b0 c the steady release of active ingredients of a molecular weight of 150 to 400 is ensured 100 g of vinyl chloride vinyl acetate copolymer are dissolved in 1200 ml of dichloromethane wherein the ratio of the monomers is 8 2 the mixture of.