Bismuth

Bismuth (more correctly - bismuth), Bismuthum, chemical symbol Bi, atomic weight 209; in the periodic system it occupies the 83rd place, and the 9th place in group V; a white, slightly reddish metal with a pronounced crystalline structure, brittle; it does not change in air or water and is not dissolved by dilute acids; it forms alloys with metals. In nature it is found in its native state and in compounds with S in the form of bismuth glance. It forms a trivalent ion Bi³⁺. The bismuth ion is colorless and with hydroxide gives an extremely weak base, consequently the phenomenon of hydrolysis in bismuth salts is sharply expressed and bismuth salts are precipitated by the addition of water; such a precipitate is again dissolved by acids (W. Ostwald). Compounds of bismuth find very wide application in medicine for both local and resorptive action. Local action. - External application. Bismuth, like other heavy metals, gives compounds with proteins, and its preparations possess both astringent and antiseptic properties. In calculation for such action, as well as for adsorbing, and also purely mechanical influence of an indifferent powder, insoluble compounds of bismuth are used on the skin and wound granulation surfaces. Dissolution of bismuth and its absorption in this case usually does not occur at all or is observed only to a very limited degree. On fresh wound surfaces, however, bismuth passes into as yet undetermined soluble compounds, which are relatively quickly absorbed and can cause severe general poisoning. - Internal application. Insoluble compounds of bismuth are almost not absorbed by the mucous membranes of the digestive tract, even in case of their inflamed condition. The action of bismuth on them is also purely local and of the same nature as in its external application: weakly astringent, limiting secretion and antiseptic. The acidic reaction of gastric contents promotes the partial dissolution of bismuth and thereby enhances its action, while the normal acidity of gastric juice is not changed by bismuth, and increased acidity is slightly lowered. Bismuth does not affect the motor function of the stomach, and the time food stays in the stomach under the influence of bismuth preparations does not change. When entering the stomach, bismuth first accumulates in the lower parts of this organ, and then distributes throughout its mucous membrane, forming as it were a protective coating, which has special importance when the integrity of the mucous membrane is impaired (ulcers). The action of bismuth on the intestinal mucosa is similar to its action on the gastric mucosa, however, bismuth preparations usually contribute to weakening of intestinal peristalsis. This depends on the above-mentioned astringent action of bismuth and on its binding of H₂S, which is one of the factors enhancing peristalsis, and finally, the protection of the mucous membrane from chemical and mechanical irritation by intestinal contents also has significance, whereby reflex intestinal peristalsis is weakened. Stools after bismuth are black in color, apparently depending on the formation of bismuth sulfide; according to Quinke, this coloring is given by reduced bismuth. Usually even very large doses of bismuth taken per os do not cause poisoning, which is explained by the difficulty of absorption of bismuth compounds. In some cases, however, in connection with not yet fully clarified conditions, poisoning is observed even when taking bismuth preparations per os. According to some authors, the presence of lactic acid in excess may play a role here, which converts bismuth into a soluble compound and promotes its absorption. Others believe that in this case other factors are also important (acidic reaction of the stomach, independently of lactic acid, presence of bacteria in the intestine, etc.). The presence of calcium carbonate, as shown in experiments on rabbits, prevents the absorption of bismuth lactate. Another factor opposite to lactic acid, according to Levaditi, is H₂S, which gives with bismuth an insoluble sulfide compound. Resorptive action. When absorbed, bismuth manifests both its toxic and special therapeutic properties. The toxicity of bismuth when introduced into the blood is high - about 1 mg per kg of body weight - and varies depending on the speed of administration and the type of animal. Bismuth poisoning can be acute and chronic. The former is observed both when using bismuth on large fresh wound surfaces, and especially experimentally in animals when introducing soluble bismuth compounds into the blood that do not precipitate protein and therefore do not cause embolism. The introduction of bismuth compounds under the skin also causes poisoning, but more slowly, and the doses for the toxic effect are much higher, especially when using insoluble compounds that only gradually dissolve. It should be noted that even soluble compounds, when introduced under the skin, are first precipitated in the form of insoluble compounds and only then dissolve. This dissolution occurs due to the conversion by the blood and juices of the body of insoluble bismuth compounds into colloidal soluble ones, and in the transfer of bismuth from the site of introduction to other organs, leukocytes participate (Zollinger). Captured by leukocytes and carried by the current of blood and lymph throughout the body, bismuth accumulates in the spleen, central nervous system and excretory organs, such as kidneys, liver, intestine, salivary glands. Bismuth was also found in sweat and tears. Urine containing bismuth darkens after a few hours, and then a black precipitate falls from it - probably bismuth sulfide, formed with the participation of the urinary flora. Although the excretion of bismuth by urine begins early - when introducing soluble salts into the blood after 1/2 hour, and insoluble compounds under the skin on the next day - it occurs slowly and is very prolonged: urine contains bismuth, according to Fournier, for 20-30 days after stopping treatment with bismuth preparations (see below), introduced during the course of treatment in amounts from 2 to 2.5 grams. In some cases, the retention of bismuth in the body was observed for much longer. Bismuth is also found in feces when using the parenteral method of administration. Some authors point to the excretion of bismuth by the mammary gland. In humans, after the application of a toxic dose, symptoms of poisoning appear after several days: first, pigmentation is found in the mouth, and a black border appears on the gums, caused by the deposition of bismuth sulfide; then stomatitis, sometimes ulcerative, which can spread to the larynx and esophagus, nausea, vomiting, gastralgia, meteorism, diarrhea, oliguria, albuminuria, cylinders in the urine, desquamation of the renal epithelium. Then comes a decline in nutrition, emaciation and cachexia; nervous symptoms appear - immobility of the occiput, increased sensitivity, convulsions and cardiac disorders (irregular pulse and weakness of the heart). The pathological-anatomical picture in bismuth poisoning is expressed in the lesion of the liver, partly stagnant, partly degenerative, and sometimes of a sclerotic nature. In the kidneys, desquamation, degeneration and necrosis of the epithelium are observed, especially of the convoluted tubules, which is the cause of the appearance in the urine of hyaline, granular and epithelial cylinders. The mucous membrane of the lower part of the intestine is colored black by bismuth sulfide. When using bismuth nitrate, in case of reduction of this compound to nitrous acid, poisoning may depend, in addition to bismuth, on the residue of nitrous acid (see). The resorptive action of bismuth has therapeutic value in the treatment of syphilis (see in detail - Syphilis, treatment). Bismuth preparations. For action on the skin, mucous membranes and for radiography are used: 1. Bismuth subnitricum s. nitricum basicum s. Magisterium Bismuti, basic bismuth nitrate [4NO₃BiO.BiOOH.4H₂O (Thorns), 71-73.5% Bi], a heavy white crystalline powder without taste or smell, almost insoluble in water, but soluble in weak acids. Externally - powders and ointments (burns). Internally 0.3-1.0 several times a day for gastritis, cardialgia, diarrhea; for stomach ulcer - 10.0-20.0 in the form of Mixturae agitandae. - 2. Bismuth subcarbonicum, basic bismuth carbonate [(BiO)₂CO₃], 85% Bi, white or yellowish-white powder, without taste or smell, insoluble in water and alcohol. The doses are the same as for the previous preparation. It is preferable for radiography - 20.0-30.0 in a paste, since the possibility of poisoning with nitrous acid is excluded. - 3. Bismuth salicylicum (subsalicylicum), basic bismuth salicylate [C₇H₆(OH)COO BiO], 56.4-58.5% Bi, tasteless white amorphous powder; insoluble in water. 0.5-1.0 pro dosi. It is also used for syphilis in the form of a 10% oil suspension (intramuscularly). The therapeutic effect is weaker than with bismogenol, biochinol and bismuthoglycolate. - 4. Bismuth subgallicum s. Dermatol, bismuth gallate [C₇H₂(OH)₃.COOBi(OH)₃], not less than 46.6% Bi, yellow, water-insoluble powder, without taste or smell. Externally in powders and ointments (10%); internally 0.2-0.5 several times a day for diarrhea. - 5. Bismuth tribromphenolicum s.

Xeroform [approximate composition- (C_eH₂Br₃O)₂BiOH·Bi₂O₃], 44.9% bismuth, yellowish, water-insoluble powder, almost tasteless with a weak odor. Externally-as an astringent and antiseptic; internally-as an antiseptic in 0.5 doses several times a day. Bismuthosa (see), compound of B. with protein, bismuthon (see). Preparations of B., used in the treatment of syphilis, are divided into soluble and colloidal, used for intravenous infusion and (less frequently) for intramuscular injections, and insoluble, used exclusively intramuscularly in oil suspensions. Among the soluble preparations are: preparations of complex tartrate salts of B. with K and Na: Sigmuth, Tartrobi, Luotal, Luol, Bismobram, Benzobismuth, Bismuto-Yatren A (solution of sodium bismuthyl-iodo-oxyquinoline-sulfate). Colloidal solutions represent the following preparations: Jonoide de Bi, Bismuthoidol, Bismuth diasporal (colloidal, highly dispersed oxide of B.). Insoluble preparations for intramuscular injections. Preparations of metallic B.: Neotrepol, in ampoules of 2 cubic cm, contains 0.192 pure metallic B. Administered in 1.5-2 cubic cm doses 2 times a week. A series consists of 15 injections. Bismuthyl, a similar preparation. Organic compounds: Trepol, complex salt of tartrate of B. with potassium and sodium, contains 64% pure metallic B., represents a suspension of white powder in oil (ampule 0.2-0.125 metallic B.). Injections are sometimes painful. Administered 2 times a week in a series of 15 injections, totaling 1.9 metallic B. Bismogenolum (German preparation), compound of B. with oxybenzoic acid (contains about 60% B.) in oil suspension. Used as trepol. Jodobismuthate of quinine, red-colored salt, contains about 20% metallic B. Rapidly releases B., which determines the rapid therapeutic effect. Quinby, contains about 20% metallic B., 50% iodine and 30% quinine. Ampoules contain 0.3 of the salt = 0.06 metallic B. Administered in series-12-20-25 injections, every 3 days. Well tolerated. Bismocoral, bismuth oxide-tetramide, suspended in acid-free olive oil. Administered 2 times a week: 0.5 bismocoral the first time and 1.0 in subsequent doses. Bijochinol, 10% oil suspension, containing 20% B., 50% iodine and 30% quinine. Brick-red color. Russian preparation, similar to Quinby. Bismutogwi, 10% oil suspension of acid tartrate of B., contains 40% bismuth. Russian preparation, similar to Trepol.

A. Likhachev.

Discovery in legal cases. Poisonings by B. are rare, but the widespread therapeutic use of basic nitrate of B. is the cause of frequent findings of B. in the viscera, vomit, etc. when examining them for poisonous metals. After destruction of the object (see Poisons, isolation) and precipitation with hydrogen sulfide, B. is obtained in the form of black sulfide of B. Unlike mercury, sulfide of B. dissolves in nitric acid of sp. gr. 1.2 (30%). The solution is evaporated on a water bath; the addition of water causes the precipitation of white basic salt of B. An alkaline solution of stannous chloride (stannite) without heating causes the precipitation of black metallic B. In concentrated solutions, potassium iodide gives a precipitate of iodide of B. or its basic salt of red or reddish-brown color, soluble in excess of the reagent. In the presence of acids (hydrochloric or organic) potassium iodide gives an orange or red coloration (0.1 mg is detected in 1 cubic cm of solution). For quantitative determination, B. is precipitated with ammonium carbonate, the basic carbonate of B. is calcined, and the oxide of B. is weighed.