The preparation of media, buffers and reagents for the manufacture and production of protein pharmaceuticals involves the mixing of extremely high quality water (water for injection or WFI) with crystal, power or liquid ingredients of high quality containing fully identified chemicals and/or impartially identified components (e.g. growth factors in fetal bovine serum (FBS) ingredients) using a recipe that has been validated.
The solvent of all media, buffers and most reagents used in the production of protein pharmaceuticals is water. In the manufacture of biologics which are most often injected intravenously during therapy, the highest level of water quality is required. That means that the manufacturing and production facility of a biotechnology company must purify its incoming water supply to water suitable for injection (WFI). The modern biotechnology manufacturing and production facility processes incoming water according to validation protocols and SOPs. The production of WFI water involves a series of validated protocols and SOPs that include carbon filtration, membrane filtration, irradiation, distillation, heating to extremely high temperatures, and reverse osmosis. WFI water is piped to areas where media, buffers and reagents will be made.
A medium supporting cellular growth, reproduction and protein secretion is necessary during fermentation or upstream processing, in the manufacture of protein pharmaceuticals. During the research and development process for a biologic, a recipe for a medium producing the greatest yield of protein for the best price is identified and the use of the medium in manufacturing the biologic is validated. Besides WFI water, media ingredients include a carbon source, usually glucose, for cellular energy production in the form of ATP; a nitrogen source, usually a pre-digested protein source to supply amino acids or specific amino acids, for production of amino acids for protein synthesis (if some amino acids that are necessary for protein synthesis cannot be synthesized then these essential amino acids must be provided); a source of sulfur which is most often the sulfur containing amino acids, methionine and cysteine in animal cells and could be a sulfur containing mineral compound for bacteria and yeast; a source of sodium, potassium, magnesium, bicarbonate, calcium and phosphate ions which can be provided in the form of minerals; and sources of trace mineral ions and vitamins (these essential nutrients are most often built into the structure of enzyme proteins, protein hormones, growth factors, channel proteins and many other proteins synthesized by the cell). Also, sometimes unknown growth factors are required that can be found in undefined media additions such as fetal bovine serum (FBS). Increasingly, however, such unknown ingredients are being eliminated from media recipes.
Buffers are necessary, during purification or downstream processing, of the protein pharmaceuticals produced by bacteria, animal cells and fungi. During the research and development process for a protein pharmaceutical, recipes for buffers for dialysis of proteins and washing, equilibrating, and eluting of chromatography columns selected for the isolation and purification of the greatest amount of protein pharmaceuticals is validated. Besides WFI water, buffers are ordinarily composed of mineral ions, amino acids, or other small molecules that can moderate the pH and ionic strength and/or influence the binding and release of protein pharmaceuticals.
Buffers are also prepared as parts of reagents used for quality control (QC) assays in the QC department of a biotechnology manufacturing facility.
REFERENCES:
Sonia Wallman, NHCTC. 1997