Plasma protein manufacturing processes

The major manufacturing process for plasma-derived products is the fractionation of human plasma, the liquid part of blood, to remove the minute amounts of plasma proteins present in each unit of plasma. To make the process commercially successful, very large quantities of plasma are mixed together and then fractionated. Dr. Elias Cohn developed the initial process in the early 1940s at Harvard University using differential cold alcohol precipitation. Essentially the same process (as modified by Oncley) is used today, with the addition of more rigorous viral inactivation techniques to increase safety. The conditions have been set to both efficiently fractionate the protein and to maximize viral partition, inactivation, or removal. Considering the... 

When mammalian red cell Hb is used as the raw material for production of a modified Hb, the requirement for the minimization of plasma proteins and red cell stroma is a rigorous and general one. Some manufacturers meet this requirement by extensive red cell washing to reduce contamination by residual plasma, controlled lysis, and careful filtration of the hemoly-sate, followed by ultrafiltration. Other manufacturers add a chromatographic purification step to this procedure. Published data indicate that the phospholipid content of the so-called stroma-free Hb resulting from either process is very low (<2pg/ml). ... 

Plasma-derived therapeutic proteins are parenteral biologies that are purified on an industrial scale. All biologies derived from human sources, such as plasma, carry the risk of viral contamination. Thus, in order to market a medicinal product derived from human plasma, manufacturers must assure the absence of specific viral contamination. Virus validation studies are performed to evaluate the capacity of a manufacturing process to remove viral contaminants. Virus clearance across three different terminal inactivation steps, low pH incubation of immunoglobulins (IgG), pasteurization of albumin, and freeze dry/dry heat treatment of plasma-derived products (Factor VIII and Protein G), is discussed in this article. The data show that, like all other upstream virus reduction steps, the methods used for terminal inactivation are process and product dependent, and that the reduction factors for an individual step may be overestimated or underestimated due to inherent limitations or inadequate designs of viral validation studies. 

Protein trafficking is the process whereby a protein manufactured within a cell is delivered (trafficked) to its desired location within the cell. In the case of hERG channels, it is the process whereby the relevant proteins are delivered to their locations within the plasma membrane. 

Ultrafiltration is used to separate and concentrate various protein types from foodstuffs, such as whey protein from cheese manufacture, egg albumen, and blood plasma proteins (Porter and Michaels, 1970). Ultrafiltration achieves separation by the use of a semi-permeable membrane. The process is carried out under hydraulic pressure. 

Human blood plasma contains over 700 different proteins (qv) (1). Some of these are used in the treatment of illness and injury and form a set of pharmaceutical products that have become essential to modem medicine (Table 1). Preparation of these products is commonly referred to as blood plasma fractionation, an activity often regarded as a branch of medical technology, but which is actually a process industry engaged in the manufacture of speciaUst biopharmaceutical products derived from a natural biological feedstock (see Pharmaceuticals). 

History. Methods for the fractionation of plasma were developed as a contribution to the U.S. war effort in the 1940s (2). Following pubHcation of a seminal treatise on the physical chemistry of proteins (3), a research group was estabUshed which was subsequendy commissioned to develop a blood volume expander for the treatment of military casualties. Process methods were developed for the preparation of a stable, physiologically acceptable solution of alburnin [103218-45-7] the principal osmotic protein in blood. Eady preparations, derived from equine and bovine plasma, caused allergic reactions when tested in humans and were replaced by products obtained from human plasma (4). Process studies were stiU being carried out in the pilot-plant laboratory at Harvard in December 1941 when the small supply of experimental product was mshed to Hawaii to treat casualties at the U.S. naval base at Pead Harbor. On January 5, 1942 the decision was made to embark on large-scale manufacture at a number of U.S. pharmaceutical plants (4,5). 

Plasma fractionation is unusual in pharmaceutical manufacturing because it involves the processing of proteins and the preparation of multiple products from a single feedstock. A wide range of unit operations are utilized to accompHsh these tasks. They are Hsted in Table 3 some are common to a number of products and all must be closely integrated. The overall manufacturing operation can be represented as a set of individual product streams, each based on the processing of an intermediate product derived from a mainstream fractionation process (Fig. 1). 

Process Rationale. The products of plasma fractionation must be both safe and efftcaceous, having an active component, protein composition, formulation, stabiUty, and dose form appropriate to the intended clinical appHcation. Processing must address a number of specific issues for each product. Different manufacturers may choose a different set or combination of unit operations for this purpose. 

Viruses (from the Latin virus referring to poison) are nonliving obligate intracellular parasites composed of protein and nucleic acid (DNA or RNA) that manipulate the host cell to produce and manufacture more viruses. Viral infection occurs by tire attachment of virus particles to specific cell receptors within the host cell. After fusion of the host cell plasma membrane with the virus outer envelope, the protein-based viral nucleocapsid (containing the viral DNA) is transported to the host cell nucleus, where components of the viral particle inhibit macromolecular synthesis by tire host cell. Herpes viral DNA and new viral nucleocapsid synthesis occurs within the host nucleus, with the acquisition of new viral envelopes via a budding process through the inner membrane of the host nucleus. The mature newly synthesized viral particles are subsequently... 

This ignorance led to alarm as the first cases appeared in haemophiliacs, who had received the blood protein factor VIII. This was not only a serious health concern but also a major commercial problem, since worldwide sales of blood products was estimated to be around two billion US dollars. For haemophiliacs, the situation was dire. Because of the large quantity of blood plasma that had to be processed in order to obtain factor VIII, and the large number of injections they needed each year, it was estimated that each patient could be exposed to the blood of up to three million donors. At this time, the manufacturers of factor VIII did not use heat-treatment procedures, as they did from 1987, but nonetheless, the causative agent appeared to be pretty rugged. The appearance of the disease in haemophiliacs rendered the name GRID inappropriate for the condition, and this was now replaced by the term Acquired Immune Deficiency Syndrome or AIDS. 

Advances in recombinant technology alleviated the problem of protein production and its purity. Through the process of recombinant DNA technology and use of nonhuman cell lines, human proteins can be manufactured free of viral contamination. This process enables production of large quantities of proteins previously difficult to obtain from human sources. Further isolation of protein from human sources is associated with a high risk of viral contamination. One such example, plasma derived clotting factor VIII isolated from human blood, resulted in transmission of viral diseases such as hepatitis and AIDS [1,2]. 

Ultrafiltration is used in many different processes at the present time. Some of these are separation of oil-water emulsions, concentration of latex particles, processing of blood and plasma, fractionation or separation of proteins, recovery of whey proteins in cheese manufacturing, removal of bacteria and other particles to sterilize wine, and clarification of fruit juices. 

Removal of pectin hazes and sus )ensions from fruit juices Recovery of lignosulphonate and vanillin from pulp/paper effluent Recovery of proteins, for example, from whey Concentration of milk solids prior to cheese manufacture Recovery of protein and enzymes from food processing effluents Fractionation of blood plasma Removal of pyrogens from water Hydrogen recovery (special membrane required)... 

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