Märkägranulointi

Märkägranulointi, also known as wet granulation, is a process used in the pharmaceutical and chemical industries to convert fine powders into larger, more flowable granules. This technique is particularly useful for improving the compressibility and handling characteristics of powders that are difficult to process in their dry state. The process involves mixing the active pharmaceutical ingredient (API) and excipients with a binding agent solution, which causes the fine particles to agglomerate into granules.

The binding agent, typically a liquid such as water, alcohol, or a hydroalcoholic solution, acts as a temporary binder. During the mixing process, the liquid wets the powder particles, allowing them to adhere to each other. The amount of liquid used is critical; too little will result in poor granule formation, while too much can lead to a sticky mass that is difficult to process. After granulation, the wet mass is dried to remove the solvent and then typically milled or sieved to achieve the desired granule size distribution.

Märkägranulointi offers several advantages. It improves powder flowability, which is essential for consistent tablet weight and content uniformity during tablet manufacturing. It also enhances compressibility, enabling the formation of robust tablets. Furthermore, wet granulation can help mask unpleasant tastes or odors of APIs and can improve the stability of certain drugs by protecting them from moisture and light. However, this method is not suitable for moisture-sensitive or heat-sensitive compounds. Common equipment used in wet granulation includes high-shear mixers, fluid bed granulators, and oscillating granulators.