Lyophilization Process for Vial Powder Injections

Views: 46 Author: Hunan Grand packing machinery Publish Time: 2025-08-08 Origin: Hunan Grand Packing Machinery

The production process for lyophilized powder vials is broadly divided into five stages:

1. Bottle washing

2. Liquid preparation

3. Filling

4. Freeze drying

5. Stoppering and capping

External processes include testing and data storage.

The above five points are only the basic outline.The freeze-drying process in point 4 will be described later.

Freeze-dried powder production-1 line

The sterile lyophilization process involves freezing the moisture in drugs or biological products at low temperatures under sterile conditions, followed by sublimation of ice crystals under vacuum to achieve drying. This process preserves the product's activity and stability, avoids thermal decomposition and deterioration, and offers good reconstitution properties with minimal contamination risk. The entire procedure must be conducted under strictly controlled temperature, freezing rate, and vacuum conditions. Next, we will examine the working principles of the equipment used in this process alongside the video.

Working principle of freeze dryer

Freeze-drying, or lyophilization, is the process of removing moisture from pharmaceutical products to maintain their long-term stability. A lyophilizer primarily consists of a product chamber, a condenser, and systems controlling vacuum, refrigeration, and heating. These components work together during the four stages of freeze-drying. Specific parameters such as temperature, pressure, and time depend on the formulation and protocol of the individual product. In most cases, the process may take anywhere from one to several days.

freeze drying

Inside the product chamber, the temperature of the shelves is lowered until solvents like water freeze. Since the product has a lower freezing point, the temperature is further reduced until the entire solution is completely frozen. While the product is freezing, the condenser is cooled to a temperature significantly lower than that of the shelves. Next, the primary drying phase (sublimation drying) begins.

Lyophilized powder sublimation drying

At this stage, the isolation valve opens, and the vacuum pump evacuates air from both chambers. As the pressure decreases, the temperature of the shelves slowly rises. The combination of higher temperature and lower pressure causes ice crystals to transform directly into vapor, a process known as sublimation. Water vapor rises from the vials and is expelled, leaving behind a partially dried product matrix. The vapor passes through the isolation valve and is captured by the condenser. The vapor naturally moves from the area of highest pressure (where sublimation occurs) to the area of lowest pressure, which is the frozen coils (cold trap) of the condenser.

fully dried product matrix

By the end of the primary drying phase, approximately 90% of the moisture has been removed, but the product is not yet fully dry. Some moisture remains bound to the product, and removing this bound water requires additional heat. Therefore, during the secondary drying (desorption drying) phase, the temperature is gradually increased to eliminate any remaining moisture bound to the product, leaving behind a completely dried product matrix.

backfill & stoppering

Once the product is fully dried, sterile process gas (such as nitrogen) is introduced into both chambers to break the vacuum and restore normal pressure. Then, the multiple shelves of the lyophilizer are pressed together, ensuring the complete insertion of the vial stoppers. Finally, the product is capped, packaged, inspected, and released for shipment to hospitals and clinics, where it is reconstituted before use for injection.

Use of freeze-dried powder