Hydrogen peroxide sterilisation

Commonly used disinfectants are ethanol 70 % or isopropyl alcohol 70 %. The disinfectant must be sterile and spore-free. This can be achieved by adding 0.125 % hydrogen peroxide, sterilisation by 0.2 pm filtration, or sterilisation by gamma radiation. Neither ethanol nor isopropyl alcohol are sporicidal, i.e. they are not effective against bacterial spores (see Table 31.4). Unless there are validation data from the manufacturer, it is recommended that the maximum in-use period for sterile disinfectants is limited to one week after opening. This should be noted on the container after it is opened. (Often the contents will be used well before then.)... 

There are a number of well-established systems for the aseptic packaging of liquids. Notable among these are those packs constructed, box form, in situ on the filling line from a cardboard, aluminium, plastic laminate sheet, such as TetraPak or Combi-box. In the TetraPak system, the packing material enters the filling machine from a feed roll the sheet contact surface is sterilised with warm hydrogen peroxide solution it is formed into a tube, and its lower end is heat-sealed across the width the tube is filled, sealed at the upper end, cut and then folded into a box shape. This produces a continuous output of filled cartons with premium utilisation of bulk storage capacity. 

The entire surface of the laminate is sterilised with hydrogen peroxide before it is filled and shaped into packs. This has proved to be a very efficient and safe technique. The filling takes place in a sterile environment which is small and has few moving parts. These are important factors that contribute to the integrity of the system. The packs are sealed through the liquid, which means they are completely filled and the contents are thus fully protected against oxidation. The brik format makes very effective use of materials and economical use of bulk volume in palletisation and distribution 93% is product and only 7% is primary and secondary packaging. 

Hydrogen peroxide theoretically constitutes an ideal steriliser, for, like ozone, it destroys bacteria without adding any foreign chemical to the water. One part m 10,000 suffices to destroy ciliate infusoria,4 although a minimum of 1 part per 1000 is necessary for the destruction... 

The drain tap of each tank was also cleaned with hydrogen peroxide (30 g kg" ), leaving the tap filled for at least 2 h. The PTFE tip which was mounted to the drain tap for filling the ampoules was cleaned in the same way. Just before filling the PTFE tip was heat-sterilised. A test was carried out to estimate the losses by evaporation during the preparation of the reference material. The test consisted of filling three ampoules with ultra pure water. After weighing, the ampoules were left at room temperature for a period of 7 days. The relative loss by evaporation was less than 0.02% /day for both types of ampoules (diameter of 40 and 30 mm for respectively CRMs 408 and 409). 

In the food industry such equipment would use either a presterilised web exposed by a removable peelable layer, or UV or hydrogen peroxide as an on-line surface sterilising agent. Currently none of these would be acceptable for a pharmaceutical operation, although use for sterile oral liquids might bear consideration. 

Since PVC and PP have low melting temperatures (<90°C), components using these materials can only be sterilised by chemicals such as hydrogen peroxide and chlorine, both of which require rinsing after sterilisation. The melt temperature of PVDF, on the other hand, is 178°C, which makes it amenable to steam sterilisation. PVDF can also be sterihsed by ozone. Since ozone has a short half-life (minutes), PVDF systems do not need rinsing after sterflisation. 

Vapour phase hydrogen peroxide has recently been introduced as a method for sterilising pharmaceutical equipment including freeze-driers. ... 

For medical devices a number of processes are available such as ethylene oxide and low-temperature hydrogen peroxide gas plasma sterilisation. 

Sterilisation Autoclave Sterile products Saturated steam Hot air Dry heat Radiation Ethylene oxide Hydrogen peroxide Plasma Membrane filtration Gas sterilisation... 

Gas sterilisation including gas plasma sterilisation Gas, penetrated with moisture, enters the material to be sterilised, which is followed by the elimination of the gas. The gas (ethylene oxide or hydrogen peroxide) alkylates the purine and pyrimidine bases in the RNA and DNA of micro-organisms. 

Gas sterilisation is performed with ethylene oxide or hydrogen peroxide gas. Sometimes peracetic acid is used, but this method is too specialised to mention here in detail. In the past (fi-om 1940) formaldehyde was used as well, but this method is rarely used anymore. Gas sterilisation is used for sterilisation of medical devices and of surfaces of pharmaceutical containers where the contents are too sensitive to the high temperature of steam sterilisation and/or cannot withstand radiation sterilisation. 

Although hydrogen peroxide has been used as a disinfectant for 150 years, the technique to reliably sterilise with this compound is 25-30 years old. The method is applied for sterilisation of medical devices in the hospital. 

The materials that need to be sterilised can be cleaned in the usual way. The packaging materials should be non-adsorbent to hydrogen peroxide. Therefore, plastics such as polyethylene and polypropylene are used instead of paper for wrapping the load. 

Process Description Hydrogen Peroxide Gas (Plasma) Sterilisation... 

Aseptic packaging. Aseptic packaging has been dominated by flexible packs for liquid foods and those containing small particle size solids suspended. The flexible packs have been somewhat varied but are mainly the polyethylene/paper/foil/polyethylene or similar brick structures sterilised with hydrogen peroxide as used in Tetrapack or Combibloc machines. 

An alternative to steam sterilisation is the chemical cold sterilisation of surfaces with vaporised hydrogen peroxide (VHP) (Figure 14.16). Hydrogen peroxide vapour is used here as the sterilisation agent. 

With continued filtration, the bacteria count on the membranes increases exponentially. Regular sterilization of the polishing loop is recommended to avoid biofouling. Commercially available external pressurized UF modules can withstand both hydrogen peroxide and hot water up to 98°C for the sterilization. Hot water sterilisation is preferred as it does not introduce any chemical into the polishing loop, and it provides a quicker rinse up time compared to hydrogen peroxide. It is important to control the ion exchange resin leach-ables in the UF feed water. The presence of such leachables can result in severe flux decline in polysulfone UF modules (Maki et al., 1992). 

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