Colloidal bismuth

The answer is d. (Hardman, pp 909-910.) It is now recognized that infection with fi pylon is a major etiologic factor in peptic ulcer disease. Bismuth salts are bactericidal for many organisms but especially for spirochetes. Colloidal bismuth salts such as bismuth subsalicylate also have a coating or cytoprotective action. Antimicrobials and GI antisecretory drugs are also used in combination with bismuth compounds. 

Widespread medicinal use of colloidal bismuth subcitrate (CBS) has prompted extensive studies of bismuth compounds involving the citrate anion. Bismuth citrate is essentially insoluble in water, but a dramatic increase in solubility with increasing pH has been exploited as a bio-ready source of soluble bismuth, a material referred to as CBS. Formulation of these solutions is complicated by the variability of the bismuth anion stoichiometry, the presence of potassium and/ or ammonium cations, the susceptibility of bismuth to oxygenation to Bi=0, and the incorporation of water in isolated solids. Consequently, a variety of formulas are classified in the literature as CBS. Solids isolated from various, often ill-defined combinations of bismuth citrate, citric acid, potassium hydroxide, or ammonium hydroxide have been assigned formulas on the basis of elemental analysis data or by determination of water and ammonia content, but are of low significance in the absence of complementary data other than thermal analysis (163), infrared spectroscopy (163), or NMR spectroscopy (164). In this context, the Merck index lists the chemical formula of CBS as KgfNHJaBieOafOHMCeHsCbh in the 11th edition (165), but in the most recent edition provides a less precise name, tripotassium dicitrato bismuthate (166). 

X-Ray Crystallographic Data for Solids Described as Colloidal Bismuth Subcitrate (Hcit = [C02CH2C(0H)(C02)CH2C02]3-)... 

Bismuth compounds have been used for treating gastrointestinal disorders for more than two centuries (451). These include bicarbonate, nitrate and salicylate salts, and colloidal bismuth subcitrate. These are all Bi(III) compounds Bi(V) is usually a strong oxidant. Their structures are largely unknown and often contain a mixture of anionic ligands. This reflects the strong tendency of Bi(III) to hydrolyze and form stable hydroxo and oxo complexes. The first pKa of Bi(III) in water is ca. 1.5. Bismuth(III) has a variable coordination number, from 3 to 10. 

III. Eradication of Helicobacter pylori C. This microorganism plays an important role in the pathogenesis of chronic gastritis and peptic ulcer disease. The combination of antibacterial drugs and omeprazole has proven effective. In case of intolerance to amoxicillin (p. 270) or clarithromycin (p. 276), metronidazole (p. 274) can be used as a substitute. Colloidal bismuth compounds are also effective however, the problem of heavy-metal exposure compromises their long-term use. 

Finally, since the microorganism Helicobacter pylori plays an important role in the pathogenesis of ulcers, antibacterial agents such as amoxicillin (4.161), metronidazole (4.162), or even colloidal bismuth compounds (e.g., 4.163) may also be used. 

Colloidal bismuth compounds Subsalicylate and citrate salts available. OTC preparations popular and have some value in travelers diarrhea due to adsorption of toxins... 

F. Huwez, et al., Acute renal failure after overdose of colloidal bismuth subcitrate. Lancet 340 1298, 1992. 

Colloidal bismuth Preparations of this compound effectively heal peptic ulcers. In addition to their antimicrobial actions (see p. 236), they inhibit the activity of pepsin, increase mucus secretion and interact with proteins in necrotic mucosal tissue to coat and protect the ulcer crater. 

CBS = colloidal bismuth subcitrate RBC = ranitidine bismuth citrate approximate formulas. 

Hruz P, Mayr M, Low R, Drewe J, Huber G. Fanconi s syndrome, acute renal failure, and tonsil ulcerations after colloidal bismuth subcitrate intoxication. Am J Kidney Dis 2002 39(3) E18. 

Akpolat I, Kahraman H, Arik N, Akpolat T, Kandemir B, Cengiz K. Acute renal failure due to overdose of colloidal bismuth. Nephrol Dial Transplant 1996 11(9) 1890-1. 

Paracelsus made the general introduction of several heavy metals into medicine in the 16th century and nowadays the particular use of bismuth compounds is focused upon the treatment of disorders of the alimentary system (14 such drugs are commonly prescribed in Britain). Several of these medicines are based upon a red viscous colloidal bismuth citrate solution containing ammonium hydroxide plus a colourant, a sweetening agent and emollients such as sorbitol or glycerine at pH = 10. 

OHljtCjHgO,),]. General prepn of colloidal bismuth solution L. Vanino, cired in Melior s vol, IX, 598 (1929). 

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