What is lyoprotectant?

In freeze-dried liquid preparations, in addition to those active, toxic or therapeutically effective ingredients, they are collectively referred to as lyoprotectants. It is different from the adjuvant, the adjuvant has a therapeutic effect, and the protective agent has no therapeutic effect.

Some liquid products can be lyophilized separately, but some liquid products are often not easily lyophilized. In order to enable some products to be lyophilized successfully, the solubility and stability of the lyophilized product can be improved, or the lyophilized product can be aesthetically pleasing, and some additional substances need to be added to the product, which are protective agents, sometimes called protection. The agent is a suspending medium, a filler, an excipient, a buffer, a base, and the like. The protectant is chemically inert and does not react with the lyophilized product.

The role of protective agents:

1. Bacteria and viruses need to grow under specific culture media, but some culture media are often difficult to separate from bacteria and viruses, and they are generally successfully freeze-dried in these culture media. For example, broth, skim, protein, etc.

2. Some active substances have a very small concentration and very little dry matter. Substances that have dried during lyophilization are carried away by the sublimated gas stream. In order to improve the concentration and increase the dry matter content, the lyophilized product can form a better agglomerate. Therefore, it is necessary to add a filler such that the concentration of the solid matter is between 4 and 25%. These fillers or excipients are: sucrose, lactose defatting, protein and hydrolysate, polyvinylpyrrolidone, dextran, sorbitol, and the like.

3. Some active substances are particularly fragile and may be harmed by physical or chemical reasons during freeze-drying. Therefore, some protective agents or antifreeze agents are added to reduce damage in freeze-drying. For example, dimethyl hydrazine, glycerin, dextran (dextran), saccharides, polyvinylpyrrolidone, and the like are added.