Hydrogen Peroxide

HYDROGEN PEROXIDE (Hydrogenium hyperoxy datum, Hydrogenium peroxy datum), H₂O₂, a syrupy liquid, transparent, colorless in thin layers, blue in thick layers, 1¹/₂ times heavier than water, with a metallic sharp taste, dissolves in any proportion in water, evaporates significantly slower than the latter. Discovered in 1818 by Thenard, obtained in chemically pure anhydrous state at the beginning of the 20th century by R. Volkenstein (crystals with melting point -0.89°). Chemically, it is a very unstable compound, easily decomposing at ordinary temperatures into oxygen and water according to the formula H₂O₂ = H₂O + O. Decomposition is strongly promoted by heating, light, vigorous shaking of the vessel with hydrogen peroxide, contact with air, especially in the presence of various catalysts and enzymes, such as colloidal metals (platinum, gold, silver), lime, manganese dioxide, erythrocytes, blood (inside and outside the organism), pus, fibrin, plant and animal tissues, infusoria, yeast fungi, bacteria, and many other cells due to the enzyme catalase. Rapid decomposition is accompanied by explosion. Decomposition is strongly favored by an alkaline nature of the solution, for example due to the dissolution of alkali contained in glass; therefore, concentrated solutions of hydrogen peroxide are stored in bottles coated inside with a layer of paraffin and closed with paraffin stoppers, since paraffin does not act catalytically on hydrogen peroxide. Decomposition is slowed by small amounts of acids (sulfuric, phosphoric, etc.), some salts (NaCl, MgCl₂, CaCl₂ up to 1%), etc. In a cool place and in the dark, solutions of hydrogen peroxide can be preserved for a very long time. The strongest commercial preparation of hydrogen peroxide is a 50% solution. Based on the amount of oxygen developed after adding hydrogen peroxide to water, a rough determination of the amount of microorganisms contained in the water can be made (Gottstein). Hydrogen peroxide can serve as both an oxidizing agent and in some cases a reducing agent. Hydrogen peroxide is found in the atmosphere (but only in the amount of 0.04-1 mg per 1 kg of air) together with ozone after thunderstorms and heavy precipitation, is almost always present in rain and snow, is formed in many oxidative processes occurring with the participation of water. It is obtained by the action of acids (for example sulfuric, but more often hydrochloric) on barium peroxide according to the formula BaO₂ + H₂SO₄ = BaSO₄ + H₂O₂. Barium sulfate precipitates in the form of a white water-insoluble precipitate, while hydrogen peroxide remains in solution. Hydrogen peroxide is also obtained from sodium peroxide and water: Na₂O₂ + 2H₂O = 2NaOH + H₂O₂. To obtain as pure hydrogen peroxide as possible, it is concentrated by evaporating water, and then distilled in quartz vessels at a pressure not exceeding 15 mm of mercury. In medicine, hydrogen peroxide is used in the form of aqueous solutions. Action on the organism. When hydrogen peroxide decomposes in cells and tissues, oxygen in statu nascendi is formed, which has an antiseptic and deodorizing effect. Adding 10-15 cm³ of a 3% solution of hydrogen peroxide to 1 liter of water reduces the number of microbes in the latter more than a hundredfold. To obtain the same effect in milk, twice as much hydrogen peroxide is necessary. Cholera and typhoid bacilli die in drinking water when hydrogen peroxide is added to it up to 1%. With a content of up to 1%, hydrogen peroxide kills Staphylococcus pyogenes aureus in a broth culture within 10 minutes. Bacillus roseus-neus is killed by a 1% solution of hydrogen peroxide within 15 minutes, anthrax spores die from a 3% solution of hydrogen peroxide within 1 hour (Kronig). According to research by Mickel, hydrogen peroxide in the concentrations commonly used is close to corrosive sublimate and significantly surpasses phenol (Shilov). The antiseptic action of hydrogen peroxide on tissues is short-lived and superficial, since it occurs only as long as all the oxygen is released. It is generally believed that for disinfecting action on wounds and ulcers, a 3% solution of hydrogen peroxide corresponds to a 1% solution of corrosive sublimate. The bactericidal action of hydrogen peroxide is greatly reduced in an environment containing many organic substances, particularly proteins. Cushny assumes that this is due to too rapid decomposition of hydrogen peroxide, as a result of which the oxygen from the dissociated state passes into the usual molecular form, which has relatively weak oxidizing and disinfecting properties; when hydrogen peroxide decomposes slowly, its oxidizing effect is stronger due to the gradual formation of elementary oxygen. According to Hamburger's data (1915), hydrogen peroxide in vitro stimulates phagocytosis, while free oxygen usually has an inhibitory effect in this regard. Enzymes are rapidly destroyed by hydrogen peroxide. The previously widely recommended use of hydrogen peroxide for preserving milk is now abandoned, because although a 0.35% hydrogen peroxide prevents the development of pathogenic bacteria in milk as well as its souring, it also destroys the enzymes and vitamins contained in milk (Heinemann) (see also Milk preservation). The use of hydrogen peroxide as a deodorizing agent and for cleaning wound surfaces, according to many authors, is due not so much to its oxidizing action as to the mechanical action of the foam from the oxygen formed, the breakdown and removal of necrotic particles, pus particles, blood clots, etc. from the wound surface. This is also the basis for cleaning teeth with hydrogen peroxide. Hydrogen peroxide also has a hemostatic effect (see Hemostatic agents) in small parenchymal hemorrhages from mucous membranes, after tooth extraction, etc.; it is believed that the cessation of bleeding occurs due to the astringent properties of hydrogen peroxide or the clotting of blood agitated by the bubbles of oxygen formed from hydrogen peroxide. The commonly used weak solutions of hydrogen peroxide hardly irritate tissues, while concentrated solutions superficially cauterize the skin epithelium and wound surface, leaving a white eschar. Small amounts of hydrogen peroxide taken orally increase the secretion of mucus in the stomach and thereby reduce the acidity of gastric juice. When administered to animals under the skin or into a vein, it rapidly decomposes, and the released oxygen creates a gas embolism in the right heart and pulmonary capillaries with symptoms of suffocation (severe shortness of breath, convulsions, death) or embolism of cerebral vessels with symptoms of hemiplegia. Cases of this kind have also been described in humans when using hydrogen peroxide for washing closed cavities (for example, the pleural cavity in empyema), when the released oxygen has no free outlet to the outside and, being under high pressure, penetrates into the veins. The same dangers represent the injection of hydrogen peroxide deep into the wound (for example, injections for the purpose of killing anaerobic microbes); gangrene has been described with subcutaneous administration. Swallowing diluted solutions of hydrogen peroxide does not cause these phenomena. With slower absorption of hydrogen peroxide, traces of it could be detected in the urine, which shows its incomplete decomposition even in the blood and tissues. The gradual accumulation of hydrogen peroxide in the body, according to some authors, caused drowsiness, slowing of cardiac activity and respiration, while according to others, for example Vershinin, a symptom complex of pulmonary edema and aortic necrosis. In medicine, freshly prepared weak solutions of hydrogen peroxide are used: externally - as an antiseptic, deodorizing, astringent and hemostatic agent in the treatment of wounds and ulcers (3%), catarrhal inflammation of the oral cavity, pharynx, throat, in ulcerative stomatitis, aphthae, carious teeth and alveolar pyorrhea (gargle from 20-30 drops of 3% solution in a large glass of water), in ophthalmic practice (20-30 drops of 3% solution in a glass of water), in the treatment of frostbite and its consequences (compresses from 1.5% solution), in hemorrhages from mucous membranes (1/4 - 1% solutions), against itching of the vagina and anus, in cancer of the uterus (tampons moistened with 1.5% solution), in gonorrhea, etc.; internally - with abnormal fermentation and putrefaction in the gastrointestinal canal (1 teaspoon of 3% solution an hour before meals). With increased acidity of gastric juice (every other day 300 cm³ of 0.5% solution together with a bun). When taken internally, it is preferable to use solid preparations of hydrogen peroxide (for example, Magnesium-Perhydrol and others), since they are more difficult to decompose, reach the intestine, preserving a sufficient amount of active oxygen, and are convenient in terms of dosing. To obtain hydrogen peroxide in solid form for medical purposes, use is made of the property of many salts (for example ammonium sulfate) and especially urea to bind hydrogen peroxide like crystallization water (Hager). Internally, a 2% solution of hydrogen peroxide is given as a chemical antidote in cases of poisoning with hydrocyanic acid, its salts (also washing the stomach with a 1-3% solution to form non-toxic oxamide) and phosphorus. Externally - as a means of destroying mustard gas. For disinfecting drinking water, 10-15 cm³ of hydrogen peroxide solution are added per 1 liter of water.

In cosmetics, hydrogen peroxide is used for cleaning and whitening teeth (wiping with cotton wool soaked in a 1-2% solution), and for coloring hair golden (after degreasing with a soda solution, treatment with a 3% solution of hydrogen peroxide until the desired color is obtained).--In technology, hydrogen peroxide is widely used for bleaching ivory, sponges, and some of the most delicate fabrics from silk, wool, etc., for which ordinary bleaching substances are dangerous, as they strongly act on the fabric itself, as well as for removing stains. The discoloration of vegetable dyes under the influence of hydrogen peroxide is explained by the action of oxygen in statu nascendi. The application of hydrogen peroxide for the restoration of old paintings and icons painted with oil paints is based on its easy release of oxygen: in oil paints there are white lead, which over time turns into lead sulfide (black in color), and the paints darken; under the action of hydrogen peroxide, lead sulfide turns into lead sulfate (white in color), and the paintings lighten and are refreshed.

Preparations. 1. Hydrogenium peroxydatum solutum (VII), seu medicinale, official solution of hydrogen peroxide in water, contains hydrogen peroxide in the amount of 3% by weight. A transparent, colorless and odorless, slightly astringent, bitter-tasting liquid, of weakly acidic reaction, easily mixed with water and alcohol. Used either undiluted or in 1-1/2-1% solutions. According to the American Pharmacopoeia, the average oral dose is 4 cm³, according to the British-from 2 to 8 cm³. In a diluted solution, hydrogen peroxide is not stable, so it is desirable to use freshly prepared solutions. - 2. Perhydrol, a 30% aqueous solution of chemically pure hydrogen peroxide. A colorless liquid, of weakly acidic reaction, sp. gr. 1.115-1.119, in original bottles, lined with paraffin inside. Like other preparations of concentrated hydrogen peroxide, it is used for the extemporaneous preparation of its therapeutic concentration solutions (for example, 1 part of perhydrol with 9 parts of distilled water will give a 3% solution of hydrogen peroxide). It has advantages over the official solution of hydrogen peroxide in terms of stability and in terms of cheaper shipping (in a smaller volume and weight).-3. Katharol (seu Hydrogenium hyperoxydatum purissimum), a 30% aqueous solution of hydrogen peroxide, sp. gr. 1.111.-4. A number of preparations similar to the previous ones, namely: Peraquin, Chemidrol, Hydrogenium peroxydatum decemplex, Liq. Hydrogenii hyperoxydati concentratus simus, etc.-5. Perhydrit (Merck), a compound of hydrogen peroxide with urea, CO(NH₂)₂·H₂O₂, with the addition (according to the manufacturer's masking instruction) of "small amounts of acetylated oxy-amino acid" for stability; contains from 34% to 36% by weight of hydrogen peroxide. A white, odorless powder, easily soluble in water with the release of hydrogen peroxide. Available in powder and in tablets of 1.0 (2-3 tablets are dissolved in 30 cm³ of water); used for preparing solutions, as well as in the form of powders with 3% boric acid.-6. Otizol (Bayer factories), a compound of 36 parts of hydrogen peroxide with 64 parts of urea with the addition of small amounts of starch for stability. A white powder, soluble in water with slight turbidity. When dissolved in warm water, oxygen is released. Produced in powder and sticks for treating wounds and fistulas, in the form of tablets for rinsing the oral cavity.-7. Nurego J (Richter factories in Budapest), similar to the two previous ones, with the addition of 0.08% citric acid for stability. A white powder, stable in dry air, easily soluble in water. Used in aqueous solutions as hydrogen peroxide.-8. Pergenol (Byk), a mixture of molecular amounts of sodium perborate and sodium bitartrate; when dissolved in water, it gives off hydrogen peroxide, boric acid, and sodium tartrate. In tablets and powder for preparing solutions of hydrogen peroxide (10 parts to 120 parts of water will give a 1% solution of hydrogen peroxide).-9. Ung. Hydrogenii peroxydati Unna consists of Hydrogenii peroxydati soluti 20.0-40.0, Adipis Lanae 20.0, Ung. cerei 10.0. MDS. Ointment.-10. Magnesium-Perhydrol (Merck), Hopogan, Magnesium peroxydatum, a non-hygroscopic powder, insoluble in water, alcohol, and ether; contains about 30% magnesium oxide and 10% active oxygen. Orally in powders and tablets of 0.25-0.5 (3-4 times a day) before or after meals, in fermentative processes in the gastro-intestinal canal, in tuberculous diarrhea, etc. Does not have an irritating or poisonous effect.-11. Zincum peroxydatum Ektogan, zinc peroxide, for powders instead of zinc oxide.