Experimental conditions for the fabrication of two new polymeric devices (i.e. films and slabs) useful for the controlled release of recombinant growth hormone (GH) are given. The release rate is controlled by the resorption profile of the vinylpyrrolidone-hydroxyethyl methacrylate (VP-HEMA) tested systems which is related to the copolymer composition. The suitability of capillary electrophoresis (CE) for following the complete preparation of the different VP-HEMA devices is shown. Moreover, CE allows simultaneous monitoring of the controlled release of GH and dissolved polymer during in vitro experiments. From these results, guidelines are given for the fabrication of polymeric devices containing protein as active drug as well as for the correct selection of conditions during in vitro experiments.