Modelling of Controlled Drug-Release in Case of Carbopol-Sodium Salicylate Matrix in Gastric Liquid

Sodium salicylate in various concentrations in Carbopol matrix, a polymer of acrylic acid, has been tested in synthetic gastric liquid for determining matter transfers controlled by transient diffusion. The liquid enters the polymer with a large swelling as a result, dissolves the drug which is then extracted from the matrix. Concentration-dependent diffusivities are found for these transfers. Modelling of these transfers using an explicit numerical method with finite differences is described. Profiles of concentrations of both materials throughout the matrix are determined. By integrating these results, matters transferred as a function of time have been calculated, giving results in good agreement with experiments.