Autoclaves and Sterilizers

Great care is needed in the design of autoclaves and sterilization cycles because of the requirement for the presence of moisture. The autoclave must be loaded to allow complete steam penetration to occur in all parts of the load before timing of the sterilization cycle commences. The time required for complete penetration, the so-called heat-up time, varies with different autoclave constmction and different types of loads and packaging materials. The time may not exceed specific limits in order to guarantee reproducibility and, for porous loads, saturated steam. The volume of each container has a considerable effect on the heatup time whenever fluids are sterilized. Thermocouples led into the chamber through a special connector are often employed to determine heatup times and peak temperatures. The pressure is refleved at the end of each sterilization cycle. Either vented containers must be used or... 

Minute needles from CHjOH. Sweetish taste with slightly bitter aftertaste. Dec 195-196 . Moderately hygroscopic. Reasonably stable to air and light, [ ] 4-28.2 (c = 5). One gram dissolves in 2.8 ml H.O. Sol in glycerol slightly sol in alcohol, acetone. pH of aq soln (1 in 20) 7.2-8.0 pH in C02-free water 8.7. Solns are most stable at pH 5-7. Rate of hydrolysis is a function of pH and is catalyzed by the presence of electrolytes. Solns are not stable to autoclaving, and sterilization by filtration is necessary. Stability data Frost, Mein tire, J. Am. Chem, Soc. 66, 425 (1944). THERAF CAT Enzyme co-factor vitamin. 

Ophthalmic ointments usually contain petrolatum as the base. The petrolatum is sterilized by dry heat and combined with the sterile dmg powder under aseptic conditions. Ophthalmic suspensions contain very fine (- 10 ji) particle sized soHds suspended in an aqueous vehicle. The vehicle is adjusted to isotonicity and viscosity-increasing excipients, chelating agents, and surfactants also may be needed. The aqueous vehicle in these cases is generally autoclaved and mixed with sterile dmg powder asceptically (30). 

A 100 ml aliquot of this medium is placed In a 500 ml Erlenmeyer flask and sterilized by autoclaving for 20 minutes under 15 psi pressure. Spores of mutant strain S. aureofaciens S1308 (ATCC No. 12,748) are washed from an agar slant Into the flask with sterile distilled water to form a suspension containing approximately 10 spores per milliliter. A 1.0 ml portion of this suspension is used to inoculate the fermentation media in the example which follows. A fermentation medium consisting of the following ingredients was prepared. 

The British Pharmacopoeia (1993) recognizes five methods for the sterilization of pharmaceutical products. These are (i) dry heat (ii) heating in an autoclave (steam sterilization) (iii) filtration (iv) ethylene oxide gas and (v) gamma or electron radiation. In addition, other approaches involving steam and formaldehyde and ultraviolet (UV) light have evolved for use in certain situations. For each method, the possible permutations of exposure conditions are numerous, but experience and product stability... 

They may also be required in industrial applications where they become part of venting systems on fermenters, centrifuges, autoclaves and freeze-dryers. Certain types of filter (membrane filters) also have an important role in sterility testing, where they can be employed to trap and concentrate contaminating organisms from solutions under... 

Principles of the methods employed to sterilize pharmaceutical products are described in Chapter 20. The British Pharmacopoeia (1993) recommends autoclaving and filtration as suitable methods applicable to aqueous liquids, and dry heat for non-aqueous and dry sohd preparatiorrs. The choice is determined largely by the ability of the formulation and container to withstand the physical stresses apphed by moist heat... 

Mineral-basal media may be sterilized by autoclaving, but for almost all organic compounds that are used as sources of C, N, S, or P, it is probably better to prepare concentrated stock solutions and sterilize these by filtration, generally using 0.2 pm cellulose nitrate or cellulose acetate filters. The same applies to solutions of vitamins, and to solutions of bicarbonate and sulfide that are components of many media used for anaerobic bacteria. 

Autoclave steam sterilization is a well-established and widely used procedure. Normally, steam enters through the top of the chamber (Fig. 9). Being lighter than air, it remains at the top of the chamber but steadily and continuously drives the air out of the chamber through the bottom vent throughout the sterilization cycle. The velocity of steam entering the... 

Dismantle the aerators. Place all the glass tubes, rubber tubes, stoppers and cotton in a paper bag, seal tight with wire staples and sterilize in an autoclave. 

Judiciously selected grades provide good impact and fatigue resistance, good stiffness and impact balance, suitability for food contact, low extractables,good organoleptic properties, the possibility of autoclave and radiation sterilization in the presence of aqueous solutions. .. 

Stock solution 2. MgS04 7H20 (4.93 g) was dissolved in 20 mL of deionized water. This solution was sterilized by autoclaving and stored as a 1 m stock solution on the bench. 

The LB medium and the test tube were sterilized by autoclaving (121 °C, 20 min), while the glucose and the kanamycin were dissolved separately in water and sterilized by filtration through a 0.2 pm filter. After allowing the LB medium to cool to room temperature, glucose and kanamycin solution were added in the appropriate amounts. 

To vahdate mineralization of toluene to CO under anoxic quinone and humus-respiring conditions, Cervantes et al. (2001) performed additional experiments using emiched phosphate-buffered basal sediments from Amsterdam petroleum harbor. After two weeks of incubation, 85% of added C-labeled toluene was observed as CO. Emiched sediment converted C-labeled toluene to in media supplemented with AQDS or with humic acid (Fig. 16.34A). There was negligible recovery of in the endogenous and sterile controls. The conversion of C-labeled toluene to was coupled to an increase in electrons recovered as AH QDS or as reduced humus (Fig. 16.34B). However, there was no toluene reduction in autoclaved sediments. These results indicate that humic substances... 

Fig. 16.39 Gas chromatograms of parathion and its products formed in nonsterile aerobic soil and in nonsterile and sterile (autoclaved) samples of prereduced (anaerobic) soil after 30 minutes equilibration. (Wahid et al. 1980)...

Ranges shown represent a composite of autoclaved and filter sterilized trials, along with trials involving non-sterilized waters. No bacterial effects are in evidence. Effects of pH are unimportant in these waters. Metal catalysis is not a factor. For a detailed analysis of the data including error gnalysis, see reference 7. ... 

The aggregation of metrizamide in solution further reduced its osmolality to about 485 mOsm kg at 300 mgl mL [ 1 ]. Unfortunately, this agent could not be sterilized by autoclaving and, consequently, had to be lyophilized and reconstituted extemporaneously. In the mid-1970s, stable nonionic compounds such as iopamidol or iohexol superseded metrizamide. Further improvement was reached by stabilization of the hydrophilic sphere against external disruption, as shown with iobitridol [2]. 

Prepare 3% agarose solution In deionized water and sterilize by autoclaving. 

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