Sterilization filtration

Positive Control Inoculated with coli showed growth after 48 h Negative Control Filtrated sterile WFI under the same conditions of the test... 

The complexity of the sterile filtration operation and the CGMP regulations require the validation of sterilizing filter systems. The validation of a sterile filtration operation can be complex, with many operational parameters and their interactions needing to be identified, controlled, and predicted for each end product to demonstrate that sterility is adequately achieved by the filtration process. In the commonly used steam sterilization process, the heat parameters are identified and in-process controls specified such that a level of sterility assurance can be reproducibly obtained. In steam sterilization, the important parameter of heat, measured by temperature, can be accurately measured and continuously monitored to ensure the operational integrity of the autoclave however, unlike steam sterilization, filtration sterilization cannot be monitored on a continuous basis throughout the process. 

The important aspect of filtration sterilization, the membrane filter me-... 

The capacity of expensive sterile and virus filters is usually increased through prefiltration. Typically 0.1 p,m-rated membranes are used for prefiltration before virus filtration. Sterile filters are protected by depth filters or 0.45 p,m membranes. Some virus inactivation operations such as solvent detergent exposure also require prefiltration for the removal of particulates that can shield vimses from the inactivating effects of solvent detergent agents. 

Pharmaceutical products can be sterilized by steam sterilization, dry-heat sterilization, filtration sterilization, gas sterilization, and ionizing-radiation sterilization. The USP provides monographs and standards for biological indicators required to test the validity of the sterilization process. These products must also be tested for pyrogens—fever-producing substances that arise from microbial contamination most likely thought to be endotoxins or lipopolysaccharide in the bacterial outer cell membrane. 

Naido NT, Price CH, McCarthy TJ. Preservative loss from ophthalmic solutions during filtration sterilization. Aust Pharm Sci 1972 1(1) 16-18. 

Examples of preservatives are phenylmercuric nitrate or acetate (0.002% w/v), chlorhexidine acetate (0.01% w/v), thiomersal (0.01% w/v) and benzalkonium chloride (0.01% w/v). Chlorocresol is too toxic to the corneal epithelium, but 8-hydroxy-quinoline and thiomersal may be used in specific instances. The principal consideration in relation to antimicrobial properties is the activity of the bactericide against Pseudomonas aeruginosa, a major source of serious nosocomial eye infections. Although benzalkonium chloride is probably the most active of the recommended preservatives, it cannot always be used because of its incompatibility with many compounds commonly used to treat eye diseases, nor should it be used to preserve eye-drops containing anaesthetics. As benzalkonium chloride reacts with natural rubbers, silicone or butyl rubber teats should be substituted and products should not be stored for more than 3 months after manufacture because silicone rubber is permeable to water vapour. As with all rubber components, the rubber teat should be pre-equilibrated with the preservative before use. Thermostable eye-drops and lotions are sterilized at 121 °C for 15 minutes. For thermolabile drugs, filtration sterilization followed by aseptic filling into sterile containers is necessary. Eye-drops in plastic bottles are prepared aseptically. 

Nylon General filtration, sterilization Displays some protein binding and good solvent inertness. ++ +... 

Polysulfone General filtration, sterilization Good flow-rate characteristics. Best for aqueous samples. + ... 

Parenteral administration requires sterile products. Aseptic production, filtration, y-irradiation, and heating are normally used to achieve sterility. Filtration sterilization of dispersed systems requires high pressure and is not applicable to particles larger than 0.2 pm. 

Sterile filtration Filtration Sterile filtration Sterile filtration... 

Inactivated biological agents should be handled in clean areas. Clean areas should also be used when handling non-infected cells isolated from multicellular organisms and, in some cases, filtration-sterilized media. 

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