Effects of the wetting liquid and ethylcellulose on the properties of atenolol-containing pellets

The aim of this study was to investigate the influence of the wetting liquid on the properties of pellets prepared by extrusion and spheronization. Different grades of ethylcellulose were used as matrix former, with microcrystalline cellulose as filler and atenolol as model active agent. Each ethylcellulose type was applied with water alone, or with a combination of water and ethanol. The formation of the matrix and the interaction of the components were evaluated via mechanical, dissolution and morphological studies on the pellets. The presence of ethanol in the wetting liquid led to a decrease in the liberation of the active agent in the first phase of the dissolution process, but also caused a reduction in the breaking hardness of the pellets. High viscosity grade ethylcellulose gave rise to a more relevant decrease in breaking hardness. The plasticity of the mass was influenced by variation of the wetting liquid.