extrusionspheronisering

Extrusionspheronisering, also known as extrusion-spheronization, is a pharmaceutical process used to form uniform spherical pellets from a moist powder mass. The method combines extrusion of a cohesive moist mass through a die with subsequent spheronization in a rapidly rotating device to yield nearly perfect spheres. It is widely employed to produce multiparticulate dosage forms such as pellets for capsules or tablet cores.

The process begins with selecting a drug blend and suitable excipients (binders, fillers, lubricants) to create a cohesive granulate. A binder solution or solvent is added to achieve an appropriate moisture content, typically enabling the mass to be extruded but not so wet as to cause clumping. The material is forced through a die or screen in an extruder to form filaments or ribbons. These extrudates are then fed into a spheronizer, where a rapidly rotating disc applies friction and shear, transforming the extrudates into spherical pellets. Through controlled processing time, speed, and moisture, the desired pellet size distribution and sphericity are obtained. The pellets are subsequently dried and cured if necessary.

Materials used are commonly lactose or microcrystalline cellulose as carriers, with binders and lubricants tailored to the API and desired release profile. The technique yields high sphericity, smooth surfaces, good flow, and uniform drug distribution, facilitating content uniformity and predictable release. Limitations include not all formulations being suitable for extrusion-spheronization, sensitivity to moisture and heat, and the need for specialized equipment. It is particularly valued for producing sustained-release pellets and for improving fill performance in capsule and tablet formulations.