Filtration is the process of removing solid particulate matter from a fluid, whether liquid or gas, using a porous medium. This versatile method finds widespread application in various pharmaceutical processes due to its adaptability. The pharmaceutical industry employs different filtration technologies tailored to the nature of the solution being processed. Some commonly utilized methods include:

Surface Filtration: Direct interception characterizes surface filtration, where pores in the filter screen allow particles of a specific size to pass through while trapping larger molecules. Also known as membrane filtration when a porous membrane is used.

Depth Filtration: This method retains particulate matter deeper within the filter than surface filtration and is primarily employed for solution clarification. Common filters include ceramic-filtered and sintered filters.

Cross-flow Filtration: Notably exemplified by nanofiltration, designed for handling low total dissolved solids water. Nanofiltration employs a membrane with pores at or below one nanometer in diameter.

Ultrafiltration: Driven by pressure, ultrafiltration is effective for separating, concentrating, and purifying specific macromolecules. Widely applied in producing vaccines, plasma, and serums, it ensures high product purity.

Cake Filtration: This technique, rooted in surface filtration, utilizes a cake formed on the membrane surface to enhance filtration efficiency. Typically employing coarse woven cloth, the filter runs a medium through the cloth, with particles bridging the holes in the fabric. This robust membrane can efficiently remove sub-micrometer colloidal particles.

In pharmaceutical production, diverse filtration methodologies cater to specific applications, employing distinct mechanisms to achieve the desired outcome. Both surface and depth filtration serve vital roles, with ongoing technological advancements introducing more efficient filters and methods for their application in the pharmaceutical industry.