tørrgranulering

Tørrgranulering, or dry granulation, is a pharmaceutical manufacturing process used to convert powder blends into granules without the use of liquid solvents. By compacting the powder into large agglomerates or ribbons and then breaking them down to the desired granule size, the method improves flow properties and compressibility for subsequent tablet or capsule production. It is particularly suited for moisture- and heat-sensitive active pharmaceutical ingredients (APIs) and for formulations that are difficult to granulate with liquids.

Two main approaches are used. Slugging, also known as roll-press granulation in some contexts, involves compressing the powder into hard slugs using a tablet press or a single-punch press, followed by milling and sieving to the target granule size. Roller compaction forms ribbons or sheets by passing the powder between rotating rollers; the ribbons are then milled and sieved into granules. In roller compaction, the use of liquid binders is typically avoided, though small amounts of dry binders may be added in some formulations to aid cohesion.

Typical process steps include blending, the primary compaction stage (slugging or roller compaction), milling of the compacted material, screening to the desired particle size, and blending with lubricants or other excipients before final compression or encapsulation. The approach is advantageous for high-drug-load formulations and for products requiring strict solvent-free processes; it also often yields improved flow and content uniformity compared with ungranulated blends.

Limitations include higher equipment costs, energy requirements, and potential challenges in achieving tight particle-size control and uniform distribution for certain powders. Regulatory control focuses on granule size distribution, flowability, hardness, moisture content, content uniformity, and dissolution performance.