Membrane filters are thin films of polymer with lots of microscopic pores. It is used in pharmaceutical manufacturing and other activities related to Pharma. Generally, the membrane is made from cellulose, polyamide or thin film compositions. Cellulose membrane filters are commonly used in microbial analysis and they are hydrophobic too. This nature of Cellulose Membrane filter can be avoided by adding 1mg/L chlorine in water.
The Cellulose membrane filters are made from different molecules but in the Pharma industry, these two types of cellulose filters are used;
- Cellulose Nitrate Membrane Filter
- Cellulose Acetate Membrane Filter
Here are the details about these widely used Cellulose Membrane Filters.
Cellulose Nitrate Membrane Filter
As the name suggests this filter is made with the reaction of the cellulose and nitric acid. Cellulose nitrate membrane is also known as nitrocellulose or CN membrane filter. It’s ideal to clear and filter the buffer and other particles when protein binding can be ignored. This type of filter is made by dissolving the nitrocellulose in natural solvents. It made a thin membrane when spread on an even surface. As it’s a kind of Cellulose membrane filter so it must have pores but the size of pore may vary. The pore size on the thin membrane depends on the evaporation rate of organic solvent. It required proper caring and gentle handling. CN membrane filter is used in sterility tests, water for injection and others.
Cellulose Acetate Membrane Filter
This type of cellulose membrane filter is also known as CA filters. It’s very low in protein binding. The low binding of these membrane filters made them ideal for protein filtering. The pore size of this membrane filter depends on the concentration of polyethylene glycol. CA is an ideal membrane filter cold sterilization, tissue culture media sterilization, and other fluid filtration.