Which of the following is NOT a method of comminution?

Comminution refers to the process of reducing the particle size of a substance, particularly in the context of pharmaceuticals where solid forms of drugs may need to be processed into finer powders for better mixing, absorption, or dosage precision.

Trituration involves grinding a substance into a fine powder, often using a mortar and pestle, which is a common comminution technique. Pulverization by intervention is similar, as it employs the use of solvents or other interventions to facilitate the breaking down of particles into finer sizes. Levigation also falls under comminution since it involves wetting a powder with a small amount of liquid and grinding it to create a smoother, finer powder.

In contrast, filtration is not a method of comminution; it is a separation technique used to remove particulates from a liquid or gas mixture, or to separate solids from fluids. It does not involve reducing the size of particles but rather segregating particles based on their size or physical properties. Therefore, identifying filtration as the option that does not fit within the methods of comminution is accurate.