RESUMO
The rate and extent of drug release from the most controlled release wax matrices are influenced by the drug loading/embedding excipient ratio of the systems. In the present study hydrophobic wax - zinc sulphate matrices with different drug loadings were prepared for the therapy of Wilson's disease. The drug release was tested by the paddle method of USP and the dissolution data were analysed. Both the dissolution rate and kinetic profile can be controlled by alteration in the quantity of embedding material. Matrices of 75% zinc sulphate loadings showed steady state diffusion-controlled matrix release with good correlation in vitro. Good absorption of zinc sulphate from the gastrointestinal tract was proven by significant elevation of serum zinc level in patients with Wilson's disease.