Pharmaceutical freeze drying for the preservation of active ingredients

Lyophilization is a technical process for removing water by sublimation drying. This takes place through a freezing phase and a drying phase of the product.The structural properties of the product are retained when water is removed, which leads to longer shelf lives and improved stability. 

When an amorphous substance is dissolved, it becomes glassy. The starting products are stabilized in the freezing phase by cryoprotectors. This is achieved by increasing viscosity or prefentional exclusion. Prefentional exclusion means that the protein is kept in its native form by adding certain substances such as polyols or carbohydrates.
A vacuum is then applied for sublimation drying, which sublimates the ice and removes the water from the frozen solution.

The lyophilization process consists of several steps. First, the product is filled into containers or vessels in liquid form. Next, it is quickly frozen, often using refrigerants such as liquid nitrogen or R729. Once the product is frozen, the pressure in the freeze dryer is reduced and the water in the product is removed by sublimation. The water passes directly from the solid phase into the gaseous phase. This process step is known as primary drying. This process can take several hours or even days, depending on the size and type of product. In the following secondary drying stage, the temperature in the product is increased in order to remove any residual water. The dissolved substance remains as a porous cake with a large surface area, which can later be easily dissolved in water again. In the final step, the dried product is sealed to keep moisture out of the environment.

Lyophilization, as explained above, is used in various industries, including food and pharmaceuticals. Freeze-drying offers several advantages over conventional drying processes such as hot air drying. Freezing the goods preserves their structural properties, which results in better rehydration. Lyophilization also makes many food and pharmaceutical products lighter and more compact, which makes logistics and storage easier. In addition, the taste and nutritional composition is preserved, as no high temperatures are used that could lead to losses or changes.

Lyophilization is a complex process that requires careful planning and monitoring. The selection of suitable freezing and drying agents and the control of temperature and pressure are crucial in order to obtain a high-quality end product. In addition, the right packaging materials must be used to protect the dried product from humidity and other environmental influences.

Another important aspect of lyophilization is the validation of the process. This involves carrying out tests to ensure that the product has the necessary characteristics and fulfills the requirements. Tests include determining the residual moisture, particle size and stability of the product.

Freeze-drying is also used in R&D to develop new products and formulations. By combining lyophilization with other techniques such as microencapsulation, innovative products with improved properties can be manufactured.

Overall, lyophilization is an important process that is used in various industries to extend the shelf life of products and improve their stability. By removing water, the structural characteristics of the product are preserved, resulting in better quality. The controlled environment and careful planning are crucial to achieving ideal results.

Lyophilization has a long history and was first developed in the 1940s. Initially, the process was mainly used to preserve blood and sera in medical research. However, they quickly realized that lyophilization could also be beneficial for other food and pharmaceutical products, and so lyophilization began to gain importance in various industries.

In the early years of lyophilization, applications were mainly focused on medical and military areas. Freeze-drying enabled the long-term storage of medicines, blood plasma and vaccines, which was particularly important in military supplies. It also enabled the production of blood products in powder form, which could be rehydrated if required.

In recent decades, significant advances have been made in lyophilization technology. The equipment and machines have been improved to make the process more efficient and controllable. New refrigerants and vacuum systems have been developed to speed up sublimation and shorten drying times. In addition, there are increased efforts in the formulation of products to further improve stability and rehydration properties.

Lyophilization could be used in other areas in the future. For example, lyophilization techniques are being developed for the manufacture of personal care products such as creams and lotions. Lyophilization could also be used in nanotechnology to produce nanostructured materials. With advancing technology and research, the possibilities for lyophilization are endless.

Overall, lyophilization offers an effective method for preserving and stabilizing products in various industries. With advances in technology and continued research, lyophilization will continue to play an important role and provide new opportunities for product development.