Steam under pressure sterilization

One can see by the complexity of these types of manufacturing procedures that much care and attention to detail must be maintained by the manufacturer. This sterile manufacturing procedure must then be validated to prove that no more than 3 containers in a lot of 3000 containers (0.1%) are nonsterile. Ultimately, it is the manufacturer s responsibility to ensure the safety and efficacy of the manufacturing process and the absence of any adverse effect on the product, such as the possible formation of substances toxic to the eye, an ever-present possibility with gas sterilization or when using ionizing radiation. For ophthalmic products sterilized by terminal sterilization (sterilization in the final sealed container, e.g., steam under pressure), the sterilization cycle must be validated to ensure sterility at a probability of 106 or greater. 

Autoclave. A vessel used for heating, cooking, or sterilizing by exposure to superheated steam under pressure. 

The medium is then sterilized to eliminate all living organisms in the vessel.,The most common method of sterilization is by moist heat (steam under pressure) in an autoclave. Generally, the autoclave is operated at approximately 15 psi at 121°C. The time of sterilization depends on the nature of the material, the type of container, and the volume. For example, test tubes of liquid media can be sterilized in 15 to 20 minutes at 121 °C. 

The medium should be exposed to steam under pressure in a validated sterilization cycle to achieve at least a 10"6 probability of survival of organisms within the medium. 

Equipment may be sterilized or disinfected by heat, chemical disinfection or a combination of both. Many tanks and reaction vessels are sterilized by steam under pressure, and small pieces of equipment and fittings may be autoclaved, but it is important that the steam has access to all surfaces. Equipment used to manufacture and pack dry powder is often sterilized by dry heat. Chemical disinfectants commonly include sodium hypochlorite and organochlorines at 50-100 ppm free residual chlorine, QACs (0.1-0.2%), 70% (v/v) ethanol in water and 1% (v/v) formaldehyde solution. The... 

Sterilization by moist heat usually involves the use of steam at temperatures in the range 121-134°C, and while alternative strategies are available for the processing of products unstable at these high temperatures, they rarely offer the same degree of sterility assurance and should be avoided if at all possible. The elevated temperatures generally associated with moist heat sterilization methods can only be achieved by the generation of steam under pressure. 

Steriliziykni by saturated steam under pressure is the classical time-proven and most economical method of inactivation of microorganisms. When a requirement for sterility arises for a new type of medical device or pharmaceutical product, steam should always be given first consideration. This is because,... 

Moist heat sterilization is achieved by exposure to saturated steam under pressure in a suitably designed chamber. In these circumstances there is an exact relationship between the steam temperature and pressure, but the pressure is used solely to obtain the temperature required and otherwise contribute nothing to the sterilization process. The time, temperature and pressure must be used to control and monitor the process. 

Autoclave—Device used to sterilize medical instruments and equipment by using steam under pressure. 

Four common types of sterilisation are in use today gas, irradiation, steam autoclave and dry heat. The two first types of sterilisation are also called low-temperature steriUsation methods, applied to single-use products and the last two types, high-temperature sterilisation methods, applied to reusable products. Many sterilisers use saturated steam under pressure, but this method is not always practical. High temperatures damage many plastics and other synthetic materials. These materials require low-temperature sterilisation. Gas (ethylene oxide, EtO) and radiation are such sterilants. 

Authority gradient an unwillingness to be trnthfnl to those in power or anthority Autoclave device used to sterilize medical instruments and eqnipment by using steam under pressure... 

Hazards of the steam sterilizer, when used for decontamination, include steam under pressure and boiling liquids (Figure 8.1). Workers must wear suitable personal protec-... 

Several methods are used to sterilize medical devices including ethylene oxide, steam under pressure, dry heat, and gamma irradiation. In recent years. E-beam sterilization has become an increasingly popular method for the sterilization of medical plastics. E-beam sterilization offers a lower cost alternative to the more common gamma and ETO sterilization techniques. In selecting a thermoplastic resin for use in medical devices it is important to consider the effects of the sterilization method on the physical and optical properties of the material. Previously a smdy was performed to determine the effects of gamma sterilization on thermoplastic resins used in medical devices In the present work, a similar study was performed after E-beam sterilization. 

A temperature control system. Although operating under pressure, temperature is the controlling factor in steam sterilization. The modern temperature controller is made up of several key elements to sense, record, and react. These are discussed in a later section. 

Moist heat offers the advantage of greater effectiveness at low temperatures. The thermal capacity of steam is much greater than that of hot air. Spores and vegetative forms of bacteria may be effectively destroyed in an autoclave employing steam (121°C) under pressure (ISpsig) for 20 min or (27psig at 132°C), for 3 min. The lag time to complete exposure of the material to be sterilized is important. 

Steam for sterilization can either be generated within the sterilizer, as with portable bench or instrument and utensil sterilizers, in which case it is constantly in contact with water and is known as wet steam, or can be supplied under pressure (350-400 kPa) from a separate boiler as dry saturated steam with no entrained water droplets. The killing potential of wet steam is the same as that of dry saturated steam at the same temperature, but it is more likely to soak a porous load, creating physical difficulties for further steam penetration. Thus, major industrial and hospital sterilizers are usually supplied with dry saturated steam and attention is paid to the removal of entrained water droplets within the supply line to prevent introduction of a water fog into the sterilizer. 

Membrane filtration application to biopharmaceutical product development is extremely important since sterile protein-peptide products can only be prepared via sterile filtration and gamma radiation steam cannot be used under pressure. There are several excellent works in the field of sterile membrane filtration.34-36 The filter media most often tested for protein formulations with minimum adsorption and maximum compatibility are mixed esters of cellulose acetate, cellulose nitrate, polysulfone, and nylon 66. Membrane filters must be tested for compatibility with the active drug substance and selected for formulations if they have the lowest adsorption and maximum compatibility with the product. 

The medium may be sterilized by steaming at 100 °C several times over a few days or by autoclaving with steam at 120 °C under pressure for 15-20 min. With a complex medium it may be necessary to autoclave some of the components separately to avoid caramelizing the sugars. 

Working Party on Pressure Steam Sterilizers (1959). Sterilization by Steam under increased Pressure. A Report to the MRC, Lancet (i), 425-435. 

---