**2.1 Air drying**

Air drying is a common method used in many industries, including the pharmaceutical industry, to remove moisture from a product or material. It involves the use of ambient air to remove moisture from the surface of the product, typically by evaporation.

The air-drying process involves exposing the material to be dried to a stream of dry, warm air. This air is typically circulated around the material to maximize

exposure and evaporation. The process is generally slow and can take several hours or even days depending on the size and thickness of the material being dried as shown in **Figure 3** [12].
