Vaccines final product

The quality control of both diphtheria and tetanus vaccines requires that the products are tested for the presence of free toxin, that is for specific toxicity due to inadequate detoxification with formalin, at the final-product stage. By this stage, however, the toxoid concentrates used in the preparation of the vaccines have been much diluted and, as the volume ofvaccine that can be inoculated into the test animals (guinea-pigs)... 

Finished-product biopharmaceuticals, along with other pharmaceuticals intended for parenteral administration, must be sterile (the one exception being live bacterial vaccines). The presence of microorganisms in the final product is unacceptable for a number of reasons ... 

Chlorination, pasteurization, and other equivalent means of disinfecting final effluents. Disinfection is generally utilized inside vaccine-antitoxins production facilities, and in some cases dechlorination may be required. 

Figure 3.9. Generalized overview of the industrial-scale manufacture of recombinant E2 classical swine fever-based vaccine, using insect cell culture production systems. Clean (uninfected) cells are initially cultured in 500-1000 litre bioreactors for several days, followed by viral addition. Upon product recovery, viral inactivating agents such as /i-propiolactone or 2-bromoethyl-iminebromide are added in order to destroy any free viral particles in the product stream. No chromatographic purification is generally undertaken as the product is substantially pure the cell culture media is protein-free and the recombinant product is the only protein exported in any quantity by the producer cells. Excipients added can include liquid paraffin and polysorbate 80 (required to generate an emulsion). Thiomersal may also be added as a preservative. The final product generally displays a shelf-life of 18 months when stored refrigerated...

The norms for medicinal production are particularly stringent. Biological products are composed of complex molecules, produced by cell lines with a relatively recent history, and difficult to characterize. Tests performed only on the final product do not guarantee consistency of production. The purification procedures should be planned and validated for the removal of potential contaminants from diverse sources cells, culture media, equipment, and reagents used in the purification or even degradation products derived from the protein itself. There are examples of products with unexpected risks that have caused serious problems such as blood contamination by HIV-1 virus between 1980 and 1985 (Bloom, 1984) or the presence of residual infectious viruses in the poliomyelitis vaccine due to inefficient inactivation (Lubiniecki et al., 1990). 

Therefore quality control (QC) testing of vaccines normally includes the following assays, which must be passed prior to material being released for use in preclinical toxicology studies sterility, endotoxin, general safety, identity, mass, potency, purity, and stability [62], These assays should be performed on the final product using the clinical formulation. 

Because many vaccines are derived from basic materials of intense pathogencity — the lethal dose of tetanus toxin for a mouse is estimated to be 3 x 10-5pg— safety testing is of paramount importance. Effective testing provides a guarantee of the safety of each batch of every product and most vaccines in the final container must pass one or more safety tests as prescribed in a pharmacopoeial monograph. This generality does not absolve a manufacturer from the need to perform in-process tests as required, but it is relaxed for those preparations that have a final formulation that makes safety tests on the final product either impractical or meaningless. 

In this respect, rDNA products are considered to be similar to biologicals produced by traditional methods, such as bacterial and viral vaccines, where adequate control of the starting materials and manufacturing procedure is just as necessary as that of the product. The guidelines therefore place considerable emphasis on in-process controls for ensuring the safety and effectiveness of the product, as well as on the comprehensive characterization of the final product itself. The validation of certain aspects of the manufacturing process, such as the ability of the purification procedure to remove unwanted materials, e.g., DNA, is also considered to be essential. 

Interest in producing large quantities of supercoiled plasmid DNA has increased as a result of gene therapy and DNA vaccines. Due to the commercial interests in these approaches, the development of production and purification strategies for gene therapy vectors has been performed in pharmaceutical companies within a confidential environment. It is thus important to describe the downstream operations for the large-scale purification of plasmid DNA to attain a final product that meets specifications and safety requuements. " ... 

As listed in Table 3, quality of the vaccine must again be confirmed for bulk plasmids, for the formulated, and for the filled final product. Apart from routine tests for plasmid identity, purity, and sterility, consistency of the product and process must be demonstrated in at least three consecutive runs of the entire process. These runs must result in a product that meets all predefined specifications. Stability of DNA vaccines must be evaluated by long-term studies to demonstrate that the defined specifications are met until the end of the envisaged shelf live. For naked DNA, it is not anticipated that stability will be an issue. 

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