The magnetic stirrer is a laboratory instrument used for liquid mixing. It is mainly used to stir or heat and stir low-viscosity liquids or solid-liquid mixtures. Its basic principle is to use the principle of magnetic field that like charges repel and opposite charges attract, and use the magnetic field to drive the magnetic stirrer placed in the container to rotate in a circle, thereby achieving the purpose of stirring the liquid.

In terms of usage, magnetic mixer is often used by biopharmaceutical companies in certain key process steps, according to the speed and shear force:

1. Low-speed, low-shear force magnetic stirrer: used for liquid-liquid mixing containing components such as proteins, peptides and other biomacromolecules, suspended cells, dissolution of easily soluble solids, mixing of easily miscible liquids, and heat transfer;

2. Medium-speed, medium-shear force magnetic stirrer: used for culture medium preparation, mixing of sterile preparations/injections without protein/peptide components, mixing of large-volume sterile liquids, preparation of large-volume sterile buffer solutions, and dissolution of large-volume easily soluble solids;

3. High-speed, high-shear force magnetic stirrer: used for emulsification of water and oil, shear dispersion of insoluble solids, increasing the dissolved oxygen content of liquids, etc.

The reason why pharmaceutical magnetic stirrers have become a popular trend in the biopharmaceutical industry is that they reduce the trouble of cleaning validation for operators while maximizing the performance of magnetic stirrers.