Freeze-drying process, different

The relative small differences in 71 for this product by layer thickness, load, freezing methods and additional ions should not be overlooked because of their consequences. The drying time is close to proportional to d in the range between 8 and 20 mm and the influence of pc is decisive for the freeze-drying process, but also the other factors are important as can be seen more clearly from the DR measurements during SD. 

The solid content and the components of the product determine its freezing and freeze-drying process. Figure 1 shows the structure of two different products with a solid of 10% and 5%, respectively [1]. If the solid content is small, <2%, usually... 

The freeze-dried product contains the freeze-dried biological material, residuals of the manufacture of the product such as buffer, and any excipient such as lactose, sucrose, mannitol, sodium chloride, or sorbitol that has been added to the product to optimize the freeze-drying process and protect product potency. The types of water present in the freeze-dried product cake may be different for each product depending on the residuals of manufacture and the excipients present the water could be surface water, bound water, or trapped water. 

The freezing process can be performed within the freeze-drying equipment or in separate lines. During freezing outside the freeze-drying line, different methods can be applied ... 

Although viruses from different animal species (e.g., porcine, canine, and bovine) were used to test the terminal freeze dry/dry heat treatment of the Koate -DVI, Replenate , and Liberate processes, the differences in parvovirus reduction and product recovery were probably due to the different formulations and freeze drying cycles of all three FVIII products. For freeze dried products, formulation and the freeze drying process are interrelated. Without the appropriate buffers and stabilizers or optimal temperatures and cycle times, many protein preparations would be denatured by the physical stresses associated with the freeze dry/dry heat treatment. 

Most solid-state characterization studies investigate the starting material and the freeze-dried end product. It will be useful and relevant to study alterations in the solid state during the different stages of the freeze-drying process, and this is enabled by low temperature XRD. The physical characterization of the phases at... 

This chapter deals with the different aspects of the freeze-drying process, beginning with the steps involved and the conditions influencing them. The state of the art in freeze-drying technology and equipment is then reviewed, and the aims and major analytical chemical applications of the technique (particularly as regards the pretreatment of solid samples) are discussed. 

The two variables most strongly affecting the freeze-drying process are pressure and temperature. Temperature (or, rather, a temperature difference) is the driving force for heat transport. Energy moves from locations of higher temperature to locations of lower temperature. Similarly, pressure differences are the driving force for mass transport. The... 

PVA could penetrate into the BC structure and enwrapped the BC fibrils. From the SEM images, it could be observed that the diameter of the composite fibrils was larger than that of unmodified BC [84]. However, the overall structure of BC and BC-PVA composite, fiber thickness, fiber distribution and three-dimensional orientations were quite similar [85]. The SEM examination of BC and BC-PVA revealed that interpenetrated networks could be formed by integrating PVA fiber into the original BC pellicle [85]. The drying method and conditions also have significant effects on the composite structure. The BC-PVA composites dehydrated by freeze-drying process [84] had a structure that was different from those dried in an incubator oven [85]. When PVA fibers are heated, they contract [86]. 

Because of the internally controlled mass transfer, drying times for atmospheric freeze-drying are longer than for the vacuum freeze-drying. The difference in drying time increases with particle size (thickness). Thus, for 5-mm-thick particles, about 2 hours are needed to reduce the moisture content from 4 kg/kg to 2 kg/kg in the vacuum process, whereas 6 hours are required... 

Table 11.1 Investment and energy costs of different drying technologies relative to the freeze-drying process...

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