Endotoxins problems

In addition to the urgent problem of capacity, manufacturers have to cope with the operating costs of production, which are increased by the need for skilled personnel and expensive media components. Another cost driver is the inherent contamination risk when using mammalian cell culture systems. All materials must be checked closely for bacterial and viral contamination, and the presence of prions and endotoxins. This affects not only the manufacturing process, but also downstream materials and even human semm albumin (HSA) used for formulations. In the end, production costs add up to 100-1000 per gram of therapeutic protein. 

Contamination with endotoxin is an important and frustrating problem in LEH manufacturing for two reasons. Firstly, hemoglobin has a strong tendency to bind endotoxin, where one hemoglobin molecule binds to four endotoxin molecules (K 3.1 x lO M) (117). Secondly, endotoxin has amphiphilicity that enables its stable insertion into lipid bilayer. Such an interaction not only presents contamination and stability problems, but also hampers accurate quantitation of endotoxin. The best possible way to prevent endotoxin contamination is to use aseptic precautions with utmost care. All the machinery, filters, and water should be endotoxin-free. Glass and metallic components may be dry-heat sterilized at about 200° C for three... 

Endotoxins can be contaminants in many preparations of biopolymers, such as in DNA preparations. They are a major problem in toxicology because they can cause a vehement, sometimes life-threatening response of the... 

With all the assays based on Clq binding, it is important to remember that the types of complexes detected are restricted by the specificity of Clq for IgM and the IgGl, IgC2, and IgC3 subclasses. The tests may also be affected by the Clq concentration in the test sample (Gl, H16, L21, M10, R8, Z3). More importantly, a number of nonimmunoglobulin substances that are Clq reactive may occur in sera and interfere with the results. Polyanions such as DNA, heparin, and bacterial endotoxins bind Clq (A7, Gl, L2, L21, S28, S39, T5, W26, Z3). C-Reactive protein reacts with Clq through a calcium-dependent bond, a problem usually circum-... 

These impurities pose risks for the safety of proteins used as therapeutics and must be removed to a final concentration below their target limit. In addition, the product stream contacts materials such as filters and resins. Extractables, such as leachates from protein A resins, can pose an immunogenic risk to the patient and must be eliminated.75 Finally, adventitious agents such as viruses and bacterial pathogens or related contaminants such as endotoxins can lead to serious problems with the safety of the protein preparation and therefore must be minimized. Table 32.6 lists concentrations for the above impurities that are generally considered acceptable in a final protein product.76... 

The general digestibility of yeast is good but several problems, i.e. potential toxicity (acute and chronic), gastrointestinal problems, nausea, vomiting, diarrhea, rashes, caused by yeast constituents (endotoxins, metabolites) emphasize the general need for refining yeast protein for human diets. 

The most important gases are ammonia, hydrogen sulfide, carbon monoxide, and methane. A number of vapors, which represent the odors of manure decomposition, such as organic acids, amines, amides, alcohols, carbonyls, and sulfides, are also produced. Respirable particles, which may be loaded with endotoxins, are also a major health problem in swine confinement operations. 

As stated previously, contaminated products injected directly into the bloodstream or instilled into the eye cause the most serious problems. Intrathecal and epidural injections are potentially hazardous procedures. In practice, epidural injections are frequently given through a bacterial filter. Injectable and ophthalmic solutions are often simple solutions and provide Gram-negative opportunist pathogens with sufficient nutrients to multiply during storage if contaminated, a bioburden of 106 CFU as well as the production of endotoxins should be expected. Total parenteral nutrition fluids, formulated for individual patients ... 

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