Wet vs. Dry Granulation
Granulation is an important process step in the manufacturing of pharmaceutical products. The goal of granulation is to take fine, non-compactable powders and turn them into coarser agglomerates that can then be pressed into tablets. Agglomerates can be composed of dry, solid granules, where each granule represents an agglomerate of primary particles with sufficient solidity. Granulates may be used directly as pharmaceuticals or serve as an intermediate product in the manufacturing of tablets or capsules. Tablets are the most commonly used form of drug delivery as they are not only easy to produce but can also be produced in large quantities.
Granulation is divided into two categories, dry and wet granulation. In the wet granulation process, dry primary powder particles are mixed with an aqueous or solvent-based granulation fluid and solidified. In the dry granulation process, agglomerates are created through mechanical pressure alone.
Dry granulation, which unlike wet granulation is a continuous process, has over the last several decades become an established procedure in the production of pharmaceutical solids. It is employed not only for products that are sensitive to moisture or temperature, but also for its cost advantages.
In comparison to wet granulation, there are no energy-intensive drying processes necessary. This saves a major investment in equipment and production space and leads to a lower cost per lot thanks to the savings in energy cost. Without a drying step, it becomes superfluous to stock up on, distill and dispose of industrial solvents.
Dry granulators guarantee a compacting process with a high material throughput of up to 400 kg/h. This allows different products and lot sizes to be produced with one machine.