LyoWorks

Eliminate Confusion about Freeze Drying

​

​​

Lyophilization, also known as freeze-drying, is a process used to remove water or solvent from a substance (sublimation), typically a pharmaceutical product, while preserving its chemical structure and integrity. It is commonly employed in the production of prescription drugs to improve their stability, extend their shelf life, and facilitate their storage and transportation.

The lyophilization process involves three main steps: freezing, primary drying, and secondary drying.

1. Freezing: The first step is to freeze the pharmaceutical product. The substance is cooled to very low temperatures, usually below its freezing point, which converts the water or solvent content into ice crystals. Freezing is typically accomplished by placing the product in a specialized freezer or using other cooling methods.

2. Primary Drying (Sublimation): Once the substance is frozen, the primary drying phase begins. In this step, the pressure is reduced, and heat is applied to the frozen product. As a result, the ice crystals directly transition from the solid state to the gaseous state (a process called sublimation) without passing through the liquid phase. This sublimation removes the majority of the water or solvent content from the substance.

   During primary drying, the frozen product is placed in a vacuum chamber to lower the surrounding pressure. The heat source, such as heating coils, is applied to the substance to supply the energy needed for sublimation. The frozen water or solvent molecules turn into vapor and are drawn out of the product.

3. Secondary Drying (Desorption): After the primary drying, some residual moisture or solvent might remain in the product. The secondary drying phase aims to remove this remaining moisture by continuing to heat the product at a lower pressure. This process involves a slower rate of heating compared to the primary drying phase. The goal is to ensure complete removal of moisture without causing any degradation or damage to the drug.

   The duration of secondary drying depends on the specific requirements of the drug being lyophilized. It may take several hours or even days to achieve the desired level of dryness.

Once the lyophilization process is complete, the drug is sealed in a moisture-resistant container to prevent reabsorption of moisture from the surrounding environment. The resulting lyophilized product is a dry, porous material that can be easily reconstituted with a suitable solvent, such as sterile water, before administration to the patient.

Lyophilization offers several advantages for prescription drugs. By removing water or solvent, it reduces the risk of microbial growth and chemical degradation. It also enhances the stability of the drug, allowing for longer shelf life and easier storage. Furthermore, the lyophilized form of the drug is often more convenient for transportation and can be reconstituted quickly when needed, improving its usability. 

LyoWorks can help you understand lyophilization and how it applies to your products.

​

​