Metabisulfite, sodium antioxidant

Epinephrine is an inherently unstable chemical in aqueous solution, even at a low pH and in the presence of an antioxidant such as sodium metabisulfite, up to 1 mg/ ml. With the passage of time, the epinephrine dose gradually decreases due to degradation into inactive compounds. If the expiry date has passed, the epinephrine dose correlates inversely with the number of months or years past that date, and will likely be lower than the dose stated on the label even if the solution appears clear and colorless. Nevertheless, if this is the only source of epinephrine available for injection, it should be used in preference to not administering epinephrine at all [32]. 

The selection of an appropriate antioxidant depends on factors such as stability, toxicity, efficiency, odor, taste, compatibility with other ingredients, and distribution phenomena between the two phases. Antioxidants that give protection primarily in the aqueous phase include sodium metabisulfite, ascorbic acid, thioglycerol, and cysteine hydrochloride. Oil-soluble antioxidants include lecithin, propyl gal-late, ascorbyl palmitate, and butylated hydroxytoluene. Vitamin E has also been used, but its virtue as a natural antioxidant has been the subject of some controversy. 

Sodium metabisulfite is an antioxidant agent widely used in pharmaceutical preparations to reduce or prevent oxidation. There are some studies, however, that have shown that metabisulfite, under specific conditions, may have indirect oxidant properties. Baker et al. [37] demonstrated that sulfite propofol emulsion, but not EDTA propofol emulsion, underwent chemical changes during a simulated intravenous infusion. Compounds were identified as propofol oxidation products. The increase of propofol oxidation products demonstrated that sulfite from metabisulfite created a strong oxidant environment when air was introduced. Lavoie et al. [38]... 

Antioxidants 223 Sodium metabisulfite Synthetic preservative and antioxidant sulfites are die biggest threat to asthmatics... 

Antioxidant Agent that inhibits oxidation and thus is used to prevent deterioration of preparations by oxidative process Ascorbic acid, ascorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, hypophosphorus acid, monothioglycerol, propyl gallate, sodium ascorbate, sodium bisulfite, sodium formaldehyde, sulfoxylate, sodium metabisulfite... 

Ascorbic acid (1) has many biological functions besides its well-known antioxidant activity. It is a functional component of many pharmaceutical and cosmetic preparations. Antioxidants such as glutathione (45) or sodium metabisulfite (Na2S205) are added... 

Sodium metabisulfite is a commonly used antioxidant. It acts by breaking up chains during autoxidation, and / or reacting with oxygen in the solution according to the following equations ... 

Buffers can also be provided in parenteral formulations to ensure the required pH needed for solubility and/or stability considerations. Other excipients included in parenteral products are preservatives (e.g., benzyl alcohol, p-hydroxybenzoate esters, and phenol), antioxidants (e.g., ascorbic acid, sodium bisulfite, sodium metabisulfite, cysteine, and butyl hydroxy anisole), surfactants (e.g., polyoxyethylene sorbitan monooleate), and emulsifying agents (e.g., polysorbates). An inert gas (such as nitrogen) can also be used to enhance drug stability. Stability and solubility can also be enhanced by the addition of complexation and chelating agents such as the ethylenediaminetetraacetic acid salts. For a more detailed list of approved excipients in parenteral products, the reader should consult the monographs within the USP. 

Salts of sulfites are the most common antioxidants in aqueous solutions. Irrespective of which sulfite salt is added, the antioxidant activity depends on its final concentration and the final pH level of the formulation commonly sodium metabisulfite is used at low... 

Sulfites and bisulfites have been used extensively as preservatives in the food industry and also in drugs and bronchodilator inhalant solutions (1,2) as preservatives. Sodium metabisulfite is used commonly as an antioxidant in foods and drugs. As an additive in various pharmaceutical products, metabisulfite can cause unpleasant adverse reactions. 

The presence of sodium metabisulfite as an antioxidant in commercial lidocaine with adrenaline significantly increased discomfort during injection (7). 

Potassium metabisulfite is used in applications similar to those of sodium metabisulfite in pharmaceuticals and in the food, brewing, and wine making industries. It is used as an antioxidant, antimicrobial preservative and sterilizing agent. 

Sodium metabisulfite is used as an antioxidant in oral, parenteral, and topical pharmaceutical formulations, at concentrations of 0.01-1.0% w/v. Primarily, sodium metabisulfite is used in acidic preparations for alkaline preparations, sodium sulfite is usually preferred see Section 18. Sodium metabisulfite also has some antimicrobial activity, which is greatest at acid pH, and may be used as a preservative in oral preparations such as syrups. 

In the food industry and in wine production, sodium metabisulfite is similarly used as an antioxidant, antimicrobial preservative, and antibrowning agent. However, at concentrations above about 550 ppm it imparts a noticeable flavor to preparations. 

Sodium metabisulfite is widely used as an antioxidant in oral, topical, and parenteral pharmaceutical formulations it is also widely used in food products. 

Although it is extensively used in a variety of preparations, sodium metabisulfite and other sulfites have been associated with a number of severe to fatal adverse reactions. " These are usually hypersensitivity-type reactions and include bronch-ospasm and anaphylaxis. Allergy to sulfite antioxidants is estimated to occur in 5-10% of asthmatics, although adverse reactions may also occur in nonasthmatics with no history of allergy. 

Sodium metabisulfite is used as an antioxidant at low pH, sodium bisulfite at intermediate pH, and sodium sulfite at higher pH values. A specification for sodium metabisulfite is contained in the Food Chemicals Codex (FCC). 

Sodium sulfite is used as an antioxidant in applications similar to those for sodium metabisulfite It is also an effective antimicrobial preservative, particularly against fungi at low pH (0.1% w/v of sodium sulfite is used). Sodium sulfite is used in cosmetics, food products, and pharmaceutical applications such as parenteral formulations, inhalations, oral formulations, and topical preparations. 

Solutions of vanillin in ethanol decompose rapidly in light to give a yellow-colored, slightly bitter tasting solution of 6,6 -dihydroxy-5,5 -dimethoxy-l,l -biphenyl-3,3 -dicarbaldehyde. Alkaline solutions also decompose rapidly to give a brown-colored solution. However, solutions stable for several months may be produced by adding sodium metabisulfite 0.2% w/v as an antioxidant. ... 

Sodium metabisulfite and thiourea have been shown to be the best antioxidants for photostabilization of sulfacetamide solutions. Sodium editate has also a stabilizing effect on sulfacetamide solutions. The activity of antioxidants in preventing the photodegradation of sulfacetamide solutions appears to depend on their redox potentials. The lower is the redox potential of antioxidant the higher is the stabilization effect (125). 

The use of common antioxidants, such as water-soluble sodium bisulfate, sodium sulfite, sodium metabisulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, L- and D-ascorbic acid, acetylcysteine, cysteine, thioglycerol, thioglycollic acid, thiolactic acid, thiourea, dithithreitol or oil-soluble propyl gallate, butylated hydroxyanisole, butylated hydroxytoluene, ascorbyl palmitate, nordihydroguaiaretic add, and a-tocopherol is widely made in pharmaceutical formulations. Oxygen-sensitive substances should be screened for their compatibility with a range of antioxidants. One of the most commonly used antioxidants is metabisulfite. It should be noted that bisulfite has also been known to catalyze... 

Antioxidant preservatives added to oral preparations are commonly ascorbic acid, citric acid and sodium metabisulfites. They are odourless and tasteless, and supposed to be non-toxic. Nevertheless, sulfites have been incriminated in allergic-type reactions, including anaphylaxis, by many routes of administration. 

Sodium metabisulfite and EDTA have been used individually as microbiological preservatives in different approved formulations of propofol injectable emulsion. The choice of antioxidant must be made with care as some are restricted by use and/or concentration in different countries. BHA is widely used in fixed oils and fats at concentrations up to 0.02% but is permitted up to 0.1% in some essential oils. Its close relative, BHT, is recommended as an alternative to tocopherol at concentrations up to 10 ppm for the stabilization of hquid paraffin. Other antioxidants widely used in emulsion formulations include the propyl, octyl and dodecyl esters of galhc acid at concentrations up to 0.001% (fixed oils and fats) and up to 0.1% (essential oils). ... 

Toners may be irritant on skin contact, and some contain sodium selenite, which may be absorbed through skin and cause toxic effects. Sulfites (potassium or sodium metabisulfite, sodium sulfite) are used as antioxidants in developers, fixers and hardeners. 

The preservative agent sodium metabisulfite is mainly used in bakeries as an antioxidant and can cause contact dermatitis. It can be used as a reducing agent in photography and caused dermatitis in a photographic technician, probably by acting as an aggravating irritative factor. Sodium metabisulfite also contains a certain amount of sodium sulfite and sodium sulfate. 

Sulfide-derived antioxidants are used as preservatives in the food, drug, cosmetic and photographic industries. They are listed as E220 to E227. Sodium metabisulfite (sodium pyrosulfite) is also used in pharmaceutical products (see Sodium Metabisulfite). 

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