576 Hydroxide

The EINECS number for potassium citrate is 212-755-5. The 6 Lewis RJ, ed. Sax’s Dangerous Properties of Industrial Materials, 11th PubChem Compound ID (CID) for potassium citrate monohydrate edn. New York: Wiley, 2004; 3026. includes 22470 and 2735208. 7 Food Chemicals Codex, 6th edn. Bethesda, MD: United States Pharmacopeia, 2008; 800. 19 Specific References 1 Elizabeth JE, Carter NJ. Potassium citrate mixture: soothing but not 20 General References harmless? Br Med J 1987; 295: 993. 2 Gabriel R. mixture: soothing but not harmless? Cole ET et al. Relations between compaction data for some crystalline [letter]. Br Med J 1987; 295: 1487. pharmaceutical materials. Pharm Acta Helv 1975; 50: 28–32. 3 Liak TL et al. The effects of drug therapy on urinary pH: excipient effects and bioactivation of methenamine. Int J Pharm 1987; 36: 233– 242. 21 Author 4 Fjellstedt E et al. A comparison of the effects of potassium citrate and CG Cable. sodium bicarbonate in the alkalinization of urine in homozygous cystinuria. Urol Res 2001; 29(5): 295–302. 5 Domrongkitchaiporn S et al. Dosage of potassium citrate in the 22 Date of Revision correction of urinary abnormalities in pediatric distal renal tubular acidosis patients. Am J Kidney Dis 2002; 39(2): 383–391. 12 January 2009.

Potassium Hydroxide

1 Nonproprietary Names to air, it rapidly absorbs carbon dioxide and water with the BP: formation of potassium carbonate. JP: Potassium Hydroxide PhEur: Potassium Hydroxide 9 Pharmacopeial Specifications USP-NF: Potassium Hydroxide See Table I.

2 Synonyms 10 Typical Properties P Caustic potash; E525; kalii hydroxidum; kalium hydroxydatum; Acidity/alkalinity pH = 13.5 (0.1 M aqueous solution) potash lye; potassium hydrate. Melting point 3608C; 3808C when anhydrous see Table II. 3 Chemical Name and CAS Registry Number Potassium hydroxide [1310-58-3] Table I: Pharmacopeial specifications for potassium hydroxide. Test JP XV PhEur 6.0 USP32–NF27 4 Empirical Formula and Molecular Weight þþþ KOH 56.11 Identification Characters — þ — Appearance of solution þþ— 5 Structural Formula Aluminum — 40.2 ppm(a) — 4 4 See Section 4. Chloride 0.05% 50 ppm — Heavy metals 430 ppm 410 ppm 40.003% Insoluble substances — — þ 6 Functional Category Iron — 410 ppm — 4 Alkalizing agent. Phosphates — 20 ppm — Potassium carbonate 42.0% 42.0% — Sodium þ 41.0% — 7 Applications in Pharmaceutical Formulation or Sulfates — 450 ppm — Technology Assay 585.0% 85.0–100.5% 585.0%

Potassium hydroxide is widely used in pharmaceutical formulations (a) If intended for use in the manufacture of hemodialysis solutions. to adjust the pH of solutions. It can also be used to react with weak acids to form salts. Therapeutically, potassium hydroxide is used in various Table II: Solubility of potassium hydroxide. dermatological applications. Solvent Solubility at 208C unless otherwise stated 8 Description (95%) 1 in 3 Potassium hydroxide occurs as a white or nearly white fused mass. Ether Practically insoluble It is available in small pellets, flakes, sticks and other shapes or Glycerin 1 in 2.5 Water 1 in 0.9 forms. It is hard and brittle and shows a crystalline fracture. 8 Potassium hydroxide is hygroscopic and deliquescent; on exposure 1 in 0.6 at 100 C Potassium Metabisulfite 577

11 Stability and Storage Conditions 16 Regulatory Status Potassium hydroxide should be stored in an airtight, nonmetallic GRAS listed. Accepted for use in Europe in certain food container in a cool, dry place. applications. Included in the FDA Inactive Ingredients Database (injections, infusions, and oral capsules and solutions). Included in 12 Incompatibilities nonparenteral and parenteral medicines licensed in the UK. Potassium hydroxide is a strong base and is incompatible with any Included in the Canadian List of Acceptable Non-medicinal compound that readily undergoes hydrolysis or oxidation. It should Ingredients. not be stored in glass or aluminum containers, and will react with acids, esters, and ethers, especially in aqueous solution. 17 Related Substances Sodium hydroxide. 13 Method of Manufacture Potassium hydroxide is made by the electrolysis of . Commercial grades may contain chlorides as well as other 18 Comments impurities. A specification for potassium hydroxide is contained in the Food Chemicals Codex (FCC).(3) 14 Safety The EINECS number for potassium hydroxide is 215-181-3. Potassium hydroxide is widely used in the pharmaceutical and food industries and is generally regarded as a nontoxic material at low 19 Specific References concentrations. At high concentrations it is a corrosive irritant to the skin, eyes, and mucous membranes. 1 Lewis RJ, ed. Sax’s Dangerous Properties of Industrial Materials, 11th edn. New York: Wiley, 2004; 3033–3034. (1) LD50 (rat, oral): 0.273 g/kg 2 Health and Safety Executive. EH40/2005: Workplace Exposure Limits. Sudbury: HSE Books, 2005 (updated 2007). http://www.hse.gov.uk/ 15 Handling Precautions coshh/table1.pdf (accessed 5 February 2009). 3 Food Chemicals Codex, 6th edn. Bethesda, MD: United States Potassium hydroxide is a corrosive irritant to the skin, eyes, and Pharmacopeia, 2008; 808. mucous membranes. The solid and solutions cause burns, often with deep ulceration. It is very toxic on ingestion and harmful on inhalation. Observe normal handling precautions appropriate to 20 General References the quantity and concentration of material handled. Gloves, eye — protection, respirator, and other protective clothing should be worn. Potassium hydroxide is strongly exothermic when dissolved in 21 Author ethanol (95%) or water, and considerable heat is generated. The AH Kibbe. reaction between potassium hydroxide solutions and acids is also strongly exothermic. In the UK, the workplace exposure limit for potassium 22 Date of Revision hydroxide has been set at 2 mg/m3 short-term.(2) 5 February 2009. P

Potassium Metabisulfite

1 Nonproprietary Names 5 Structural Formula BP: Potassium Metabisulphite See Section 4. PhEur: Potassium Metabisulphite USP-NF: Potassium Metabisulfite

6 Functional Category 2 Synonyms Antimicrobial preservative; antioxidant. Disulfurous acid; dipotassium pyrosulfite; dipotassium salt; E224; kali disulfis; potassium pyrosulfite.

3 Chemical Name and CAS Registry Number 7 Applications in Pharmaceutical Formulation or Dipotassium pyrosulfite [16731-55-8] Technology Potassium metabisulfite is used in applications similar to those of in pharmaceuticals, and in the food, , 4 Empirical Formula and Molecular Weight and wine making industries. It is used as an antioxidant, K2S2O5 222.32 antimicrobial preservative and sterilizing agent.