![]() ![]() ![]() However, during storage, crystallization of sugars can occur, even if the storage temperature is significantly below the glass transition temperature (T g). To fulfil this stabilizing effect, the sugar has to stay amorphous during the storage time of the product. In particular, sugars can mimic water with their hydroxyl groups, thereby supporting the native conformation of the antibody upon lyophilization based on the water replacement theory. Those excipients are able to protect and sustain the structure of biotherapeutics, including antibodies. To successfully freeze-dry those materials, sugars, such as sucrose or trehalose, are used as bulking agents and lyoprotectants. Thus, freeze- or spray-drying can be used to achieve long-term stability of these products upon removal of water. Those entities face degradation problems during shipment and long-term storage when kept in their liquid formulation. The amount of biological therapeutics has strongly increased in recent years. Furthermore, the study shows that polysorbate 20 strongly accelerates crystallization of sucrose and that the freezing step itself has a strong impact on the relaxation phenomena that is not levelled out by primary and secondary drying. Samples that crystallized during the study time of 12 months showed a promising correlation between their relaxation time and crystallization behavior upon storage. The amorphous formulations were created by different freeze-drying processes only differing in their freezing step (random nucleation additional annealing step of 1.5 h and 3 h, controlled nucleation quench cooling). ![]() Storage conditions of 25 ☌ and 40 ☌ are examined and five model formulations containing either sucrose or trehalose with different concentrations of an IgG 1 antibody are investigated. The relaxation curve of a fresh sample recorded within 12 h after lyophilization is correlated with the long-term crystallization time at the same temperature. This study applies isothermal microcalorimetry to predict long-term crystallization during product storage time. The natural size, composition and consistency of the sample are retained.There is a lack of methods to predict the isothermal crystallization behavior of amorphous freeze-dried formulations stored below the glass transition temperature. With freeze drying, both solids and liquids can be preserved without damaging their basic chemical structure. ![]() Advantages of Freeze Drying Starter Cultures The product can easily be re-hydrated using water and in some cases can be used directly in its freeze-dried form. This process retains the physical structure of the product and preserves it for storage and/or transport. A gradual temperature rise extracts all remaining 'bound' moisture from the specimen. The vapour collects on a condenser, turns back into ice and is removed. Since then freeze drying has been applied to the food industry and is now a standard process used to increase the shelf-life of many products that would otherwise spoil.įreeze drying uses a process called lyophilization to gently freeze the specimen and extract the water in the form of vapour using a high-pressure vacuum. The freeze drying process was developed during the Second World War for preserving medical supplies that required refrigeration. Freeze drying is an effective way to preserve starter cultures. A starter culture is a microbiological culture which actually performs fermentation. Starter cultures are used to assist the fermentation process in preparation of various foods and fermented drinks. ![]()
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