*1.4.2 Grinding methods*

There are two distinct methods for producing co-crystals through grinding [51, 54, 55]. The first technique, known as neat grinding or dry grinding, entails mixing the drug and coformer components together and then physically pounding them into powder using a mortar and pestle, a ball mill or a vibratory mill (mechanically). The

second method for creating co-crystals through grinding involves adding small amounts of a suitable solvent. This method is known as liquid-assisted grinding, also known as solvent drop, or wet co-grinding. By adding small amounts of a suitable solvent, the kinetics of co-crystal formation by grinding can be significantly increased [56].
