Hydrophobic zinc sulphate wax matrices with different drug loadings were prepared for the individual hospital therapy of Wilson's disease. The drug release parameters, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) of the samples were analysed. The release mechanisms from matrices of 75% and 80% w/w zinc sulphate loadings were described with good correlation by the semi-empirical Fikkian diffusion based release model. Besides the zinc sulphate diffusion through the pores of the wax matrices, the parallel diffusion of zinc sulphate from the matrix surface is dominant in the case of samples of 83% and 90%w/w drug loadings. The combination of SEM and EDS analysis visualizes the morphology of the matrices and the related composition thus explaining the differences in the release characteristics.