570 Bicarbonate

the eyes and skin. Eye protection and gloves are recommended. 19 Specific References When exposed to heat, and when heated to decomposition, 1 FAO/WHO. Toxicological evaluation of certain food additives with a potassium benzoate emits acrid smoke and irritating fumes. review of general principles and of specifications. Seventeenth report of the joint FAO/WHO expert committee on food additives. World Health Organ Tech Rep Ser 1974; No. 539. 16 Regulatory Status 2 FAO/WHO. Evaluation of certain food additives and contaminants. GRAS listed. Accepted as a food additive in Europe. Included in the Twenty-seventh report of the joint FAO/WHO expert committee on Canadian List of Acceptable Non-medicinal Ingredients. food additives. World Health Organ Tech Rep Ser 1983; No. 696. 20 General References 17 Related Substances — ; . 21 Author 18 Comments CP McCoy. The EINECS number for potassium benzoate is 209-481-3. The PubChem Compound ID (CID) for potassium benzoate is 22 Date of Revision 23661960. 30 January 2009.

Potassium Bicarbonate

1 Nonproprietary Names formulations, as reaction with gastric acid can be sufficient to cause BP: Potassium Bicarbonate effervescence and product disintegration. Potassium bicarbonate has also been investigated as a gas- PhEur: Potassium Hydrogen Carbonate forming agent in alginate raft systems.(1,2) The effects of potassium USP: Potassium Bicarbonate bicarbonate on the stability and dissolution of paracetamol and ibuprofen have been described.(3) 2 Synonyms Potassium bicarbonate is also used in food applications as an P monopotassium ; E501; kalii hydrogenocarbo- alkali and a leavening agent, and is a component of baking powder. nas; monopotassium carbonate; potassium acid carbonate; potas- Therapeutically, potassium bicarbonate is used as an alternative sium hydrogen carbonate. to sodium bicarbonate in the treatment of certain types of metabolic acidosis. It is also used as an antacid to neutralize acid secretions in 3 Chemical Name and CAS Registry Number the gastrointestinal tract and as a potassium supplement. Potassium bicarbonate [298-14-6] 8 Description 4 Empirical Formula and Molecular Weight Potassium bicarbonate occurs as colorless, transparent crystals or as a white granular or crystalline powder. It is odorless, with a saline or KHCO3 100.11 weakly alkaline taste.

5 Structural Formula 9 Pharmacopeial Specifications See Section 4. See Table I.

6 Functional Category Table I: Pharmacopeial specifications for potassium bicarbonate. Alkalizing agent; therapeutic agent. Test PhEur 6.0 USP 32

7 Applications in Pharmaceutical Formulation or Identification þþ þ Technology Characters — Appearance þ — As an excipient, potassium bicarbonate is generally used in Carbonates at pH 4 8.6 þ — formulations as a source of carbon dioxide in effervescent Normal carbonates — 42.5% preparations, at concentrations of 25–50% w/w. It is of particular Chloride 4150 ppm — 4 use in formulations where sodium bicarbonate is unsuitable, for Sulfate 150 ppm — Ammonium 420 ppm — example, when the presence of sodium ions in a formulation needs Calcium 4100 ppm — to be limited or is undesirable. Potassium bicarbonate is often Heavy metals 410 ppm 40.001% formulated with or tartaric acid in effervescent tablets or Iron 420 ppm — granules; on contact with water, carbon dioxide is released through Sodium 40.5% — chemical reaction, and the product disintegrates. On occasion, the Loss on drying — 40.3% presence of potassium bicarbonate alone may be sufficient in tablet Assay 99.0–101.0% 99.5–101.5% Potassium Bicarbonate 571

10 Typical Properties 16 Regulatory Status Acidity/alkalinity pH = 8.2 (for a 0.1 M aqueous solution); a 5% GRAS listed. Accepted as a food additive in Europe (the solution in water has a pH of 48.6. E501 refers to potassium carbonates). Included in nonparenteral Soluble 1 in 4.5 of water at 08C, 1 in 2.8 of water at medicines licensed in the UK and USA (chewable tablets; 208C, 1 in 2 of water at 508C; practically insoluble in effervescent granules; effervescent tablets; lozenges; oral granules; (95%). oral suspensions; powder for oral solutions). Included in the Specific gravity 2.17 Canadian List of Acceptable Non-medicinal Ingredients.

11 Stability and Storage Conditions 17 Related Substances Potassium bicarbonate should be stored in a well-closed container Sodium bicarbonate. in a cool, dry location. Potassium bicarbonate is stable in air at normal temperatures, but when heated to 100–2008C in the dry 18 Comments state, or in solution, it is gradually converted to potassium One gram of potassium bicarbonate represents approximately carbonate. 10 mmol of potassium and of bicarbonate; 2.56 g of potassium bicarbonate is approximately equivalent to 1 g of potassium. 12 Incompatibilities A specification for potassium bicarbonate is contained in the Food Chemicals Codex (FCC).(4) Potassium bicarbonate reacts with acids and acidic salts with the The EINECS number for potassium bicarbonate is 206-059-0. evolution of carbon dioxide. The PubChem Compound ID (CID) for potassium bicarbonate is 516893. 13 Method of Manufacture Potassium bicarbonate can be made by passing carbon dioxide into 19 Specific References a concentrated solution of potassium carbonate, or by exposing 1 Johnson FA et al. The effects of alginate molecular structure and moist potassium carbonate to carbon dioxide, preferably under formulation variables on the physical characteristics of alginate raft moderate pressure. systems. Int J Pharm 1997; 159: 35–42. Potassium bicarbonate also occurs naturally in the mineral 2 Johnson FA et al. The use of image analysis as a means of monitoring calcinite. bubble formation in alginate rafts. Int J Pharm 1998; 170: 179–185. 3 Shaw LR et al. The effect of selected water-soluble excipients on the dissolution of paracetamol and ibuprofen. Drug Dev Ind Pharm 2005; 14 Safety 31(6): 515–525. Potassium bicarbonate is used in cosmetics, foods, and oral 4 Food Chemicals Codex, 6th edn. Bethesda, MD: United States Pharmacopeia, 2008; 801. pharmaceutical formulations, where it is generally regarded as a relatively nontoxic and nonirritant material when used as an excipient. However, excessive consumption of potassium bicarbo- 20 General References nate or other potassium salts may produce toxic manifestations of — hyperkalemia. 21 Author P 15 Handling Precautions CG Cable. Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are 22 Date of Revision recommended. 4 March 2009.