Correlation of extrusion forces, raw materials and sphere characteristics.

This communication reports on the correlation between extrusion forces and sphere characteristics. Dicalcium phosphate dihydrate, alpha-lactose monohydrate and anhydrous beta-lactose were models for respectively an insoluble, a medium soluble and a highly soluble drug and were used to produce spheres. Phase diagrams for ternary mixtures consisting of microcrystalline cellulose, water and a third excipient were constructed. The region where good spheres were obtained correlated well with the area of extrusion forces between 630 and 1260 N. This correlation was seen for the insoluble, the medium and the highly soluble products.