Activation with sodium bisulfite

HES is produced from 93—96% dextrose hydrolyzate that has been clarified, carbon-treated, ion-exchanged, and evaporated to 40—50% dry basis. Magnesium is added at a level of 0.5—5 mAf as a cofactor to maintain isomerase stabiUty and to prevent enzyme inhibition by trace amounts of residual calcium. The feed may also be deaerated or treated with sodium bisulfite at a level of 1—2-mAf SO2 to prevent oxidation of the enzyme and a resulting loss in activity. 

The anticonvulsant activity of some 1,3-benzisoxazoles was discovered in routine testing. One of the more interesting of the subsequent analogues prepared was zonisamide (39). One of its syntheses starts with l,2-benzisoxazole-3-acetic acid (36) which is brominated and subsequently decarboxylated to give 37. Displacement of halogen in 37 with sodium bisulfite interestingly... 

All dichloromethane examined showed 2-14 ppm of formaldehyde contamination. Several clean up methods were applied to remove formaldehyde such as washing with sodium bisulfite, treatment with active charcoal of Porapak Q porous polymer without success. Trace levels of formaldehyde in solvents may be impossible to remove. Therefore, chloroform was used as the solvent for formaldehyde analysis in further experiments. The amount of contaminant obtained from a blank solvent was always subtracted from the values of actual results. Dichloromethane was, however, used for methyl glyoxal analysis. The extraction efficiency of chloroform and dichloromethane was almost identical. Dichloromethane was easier to use for a liquid-liquid continuous extraction than chloroform because of its lower boiling point. 

The method of Kimura et al. is fast and suitable for routine measurement of vitamin status, yet it also has flexibility to measure the other vitamers when required in, e.g., metabolic studies of PN supplementation. Figure 9 shows a chromatogram obtained with plasma analysis according to Kimura et al. (77). On-column derivatization with sodium bisulfite has also been used by Kurioka et al., who used a graphitic carbon column to separate the biologically active B vitamers and 4-PA within 30 min (146). 

Oxidant Removal The presence of oxidizers such as chlorine or ozone can degrade polyamide RO membranes, causing a drop in salt retention. Cellulosic membranes are less sensitive to attack. Addition of 1.5 to 6 mg sodium bisulfite/ppm chlorine or contacting with activated carbon will remove oxidizers. Vacuum degassing with a hydrophobic filter module is also used. 

Stablizers. Stabilizers are ingredients added to a formula to decrease the rate of decomposition of the active ingredients. Antioxidants are the principal stabilizers added to some ophthalmic solutions, primarily those containing epinephrine and other oxidizable drugs. Sodium bisulfite or metabisulfite are used in concentration up to 0.3% in epinephrine hydrochloride and bitartrate solutions. Epinephrine borate solutions have a pH range of 5.5 7.5 and offer a more difficult challenge to formulators who seek to prevent oxidation. Several patented antioxidant systems have been developed specifically for this compound. These consist of ascorbic acid and acetylcysteine, and sodium bisulfite and 8-hydroxyquinoline. Isoascorbic acid is also an effective antioxidant for this drug. Sodium thiosulfate is used with sodium sulfacetamide solutions. 

By far most of the reports on addition reactions of hetero-nucleophiles to activated dienes deal with sulfur-nucleophiles17,48,80,120-137, in particular in the synthesis of 7/3-sulfur-substituted steroids which, like their carbon-substituted counterparts (Section n.A), are of interest because of their ability to inhibit the biosynthesis of estrogens80,129-137. Early investigations17,120-122 concentrated on simple acyclic Michael acceptors like methyl sorbate and 2,4-pentadienenitrile. Bravo and coworkers120 observed the formation of a 3 1 mixture of the 1,6- and 1,4-adduct in the reaction of methyl sorbate with methanethiol in basic medium (equation 39). In contrast to this, 2,4-pentadienenitrile adds various thiols regioselectively at C-5, i.e. in a 1,6-fashion (equation 40)17,121,122, and the same is true for reactions of this substrate with hydrogen sulfide (equation 41), sodium bisulfite and ethyl thioglycolate17. 

A Perkin-Elmer Model 21 infrared spectrophotometer was used to detect and to estimate the hydroxylic and carbonyl functions in the oxidized product mixtures. The organic hydroperoxide and peroxide functional groups in the product mixtures were determined by an iodine liberation and titration procedure (11). In order to get reproducible results, it is necessary to pretreat the olefins with about 10 weight % activated silica or alumina for several hours with agitation to remove adventitious peroxides and impurities. Sodium bisulfite solution rapidly destroys hydroperoxides but does not destroy peroxides completely. The hydroperoxides and peroxides decomposed extensively during attempted distillation at about 1 mm. of Hg partial vacuum. We had some success in concentration by liquid chromatography over silica gel the unconverted olefins are eluted with n-hexanes, and a hydroperoxide-peroxide... 

Streptomycin was inactivated by reducing and oxidizing agents. The bacteriostatic-activity of this antibiotic for Escherichia coli was reduced in the presence of cysteine, sodium thioglycolate, stannous chloride, sodium bisulfite, sodium hydrosulfide, sodium formate and sodium thiosulfate. Cysteine was the most active. Denkelwater, Cook and Tishler found that the cysteine inactivation of streptomycin could be reversed by iodine presumably cystine was formed during this process. Rake and Donovick inactivated streptomycin with semi-carbazide hydrochloride in order to test the sterility of concentrated streptomycin solutions. The inactivation of streptomycin by compounds containing sulfhydryl groups has been discussed by Cavallito. ... 

The products shown in Table I, column 4, were obtained and identified by the following procedure. In each case an aliquot equal to that used for active oxygen determinations (usually 0.5 to 1.0 cc.) was added at 0° C. to a five- to tenfold excess of sodium bisulfite in 10 cc. of water. The solution was then allowed to warm to room temperature and, if no volatile compounds were expected, it was warmed slightly. Then a twofold excess of 2,4-dinitrophenylhydrazine reagent was added and the mixture was heated on the water bath for 0.5 hour. After cooling and adding water if necessary, the precipitate formed was separated, washed with water, and dried in the desiccator under reduced pressure. 

To eliminate residual free chlorine from hquid, granular activated carbon adsorption or chemical reduction (with reducing agents, such as sulfur dioxide, sodium bisulfite, and sodium metabisulfite) are the most common processes for dechlorination. Ultraviolet (UV) irradiation process is gaining wider acceptance as a dechlorination process (30,45,46, 60,61). 

Solutions of levarterenol bitartrate in the presence of sodium bisulfite could be sterilized at 1150C for 30 minutes with apparent negligible loss of activity.23... 

Purification of 5-AS, according to Ellens and Gielkens (1980), is easy 5 g of 5-AS and 5 g of sodium bisulfite are dissolved in 550 ml deionized water at 80 C. This temperature is maintained, while stirring, for 10 min. Activated charcoal is then added (2 g) and the suspension is mixed for 5 min. The hot solution is filtered and then cooled to 4°C. The precipitate is washed twice with 5 ml water at 4°C, and dried in the dark. The purified 5-AS is redissolved (very soluble) at a concentration of 1 g/1 in 10 mM sodium phosphate buffer, pH 6.0, containing 0.1 mM EDTA, and stored at (20" C. Upon thawing a precipitate is usually present which readily redissolves by bringing the container in hot water to room temperature. Peroxide is added just before use. 

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