Nonproprietary Names

USP:Acesulfame Potassium
PhEur:Acesulfame Potassium USP-NF: Acesulfame Potassium

Synonyms

Acesulfame K; ace K; acesulfamum kalicum; E950; 6-methyl-3,4dihydro-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide potassium salt; potassium 6-methyl-2,2-dioxo-oxathiazin-4-olate; Sunett; Sweet One.

Chemical Name and CAS Registry Number

6-Methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide potassium salt [55589-62-3]

Empirical Formula and Molecular Weight

C4H4KNO4S 201.24

Structural Formula

Functional Category

Sweetening agent.

Applications in Pharmaceutical Formulation or Technology

Technology Acesulfame potassium is used as an intense sweetening agent in cosmetics, foods, beverage products, table-top sweeteners, vitamin and pharmaceutical preparations, including powder mixes, tablets, and liquid products. It is widely used as a sugar substitute in compounded formulations,(1) and as a toothpaste sweetener.(2) The approximate sweetening power is 180–200 times that of sucrose, similar to aspartame, about one-third as sweet as sucralose, one-half as sweet as sodium saccharin, and about 4-5 times sweeter than sodium cyclamate.(3) It enhances flavor systems and can be used to mask some unpleasant taste characteristics.

Description

Acesulfame potassium occurs as a colorless to white-colored, odorless, crystalline powder with an intensely sweet taste.

Pharmacopeial Specifications

See Table I.

Typical Properties

Acidity/alkalinity pH = 5.5–7.5 (1% w/v aqueous solution) Bonding index 0.007(4) Brittle fracture index 0.08(4) Density (bulk) 1.04g/cm3 (4) Density (tapped) 1.28g/cm3 (4) Elastic modulus 4000MPa(4) Flowability 19% (Carr compressibility index)(4) Melting point 2508C NIR spectra see Figure 1. Solubility see Table II. SEM 1: Excipient: acesulfame potassium; magnification: 150; voltage: 5 kV.1100 1300 1500 1700 1900 2100 2300 2500 Wavelength/nm Figure 1: Near-infrared spectrum of acesulfame potassium measured by reflectance. Table I: Pharmacopeial specifications for acesulfame potassium. Test PhEur 6.0 USP32–NF27 Characters Identification Appearance of solution Acidity or alkalinity Acetylacetamide þ þ þ þ 0.125% — þ — þ — Impurity B(a) 420 ppm — Unspecified impurities 40.1% 40.002% Total impurities 40.1% — Fluorides 43 ppm 40.0003% Heavy metals 45 ppm 410 mg/g Loss on drying 41.0% 41.0% Assay (dried basis) 99.0–101.0% 99.0–101.0% (a) Impurity B is 5-chloro-6-methyl-1,2,3-oxathiazin-4(3H)-one 2,2-dioxide. Table II: Solubility of acesulfame potassium.(3) Solvent Solubility at 208C unless otherwise stated Ethanol 1 in 1000 Ethanol (50%) 1 in 10 Ethanol (15%) 1 in 4.5 Water 1 in 6.7 at 08C 1 in 3.7 at 208C 1 in 0.77 at 1008C Specific volume 0.538cm3/g(5) Surface tension 73.2mN/m(6) (1% w/v aqueous solution at 208C Tensile strength 0.5MPa(4) Viscoelastic index 2.6(4)

Stability and Storage Conditions

Acesulfame potassium possesses good stability. In the bulk form it shows no sign of decomposition at ambient temperature over many years. In aqueous solutions (pH 3.0–3.5 at 208C) no reduction in sweetness was observed over a period of approximately 2 years. Stability at elevated temperatures is good, although some decomposition was noted following storage at 408C for several months. Sterilization and pasteurization do not affect the taste of acesulfame potassium.(7) The bulk material should be stored in a well-closed container in a cool, dry place and protected from light.

Incompatibilities

—

Method of Manufacture

Acesulfame potassium is synthesized from acetoacetic acid tertbutyl ester and fluorosulfonyl isocyanate. The resulting compound is transformed to fluorosulfonyl acetoacetic acid amide, which is then cyclized in the presence of potassium hydroxide to form the oxathiazinone dioxide ring system. Because of the strong acidity of this compound, the potassium salt is produced directly.(8) An alternative synthesis route for acesulfame potassium starts with the reaction between diketene and amidosulfonic acid. In the presence of dehydrating agents, and after neutralization with potassium hydroxide, acesulfame potassium is formed.

Safety

Acesulfame potassium is widely used in beverages, cosmetics, foods, and pharmaceutical formulations, and is generally regarded as a relatively nontoxic and nonirritant material. Pharmacokinetic studies have shown that acesulfame potassium is not metabolized and is rapidly excreted unchanged in the urine. Long-term feeding studies in rats and dogs showed no evidence to suggest acesulfame potassium is mutagenic or carcinogenic.(9) The WHO has set an acceptable daily intake for acesulfame potassium of up to 15mg/kg body-weight.(9) The Scientific Committee for Foods of the European Union has set a daily intake value of up to 9mg/kg of body-weight.(3) LD50 (rat, IP): 2.2g/kg(7) LD50 (rat, oral): 6.9–8.0g/kg

Handling Precautions

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection, gloves, and a dust mask are recommended.

Regulatory Status

Included in the FDA Inactive Ingredients Database for oral and sublingual preparations. Included in the Canadian List of Acceptable Non-medicinal Ingredients. Accepted for use in Europe as a food additive. It is also accepted for use in certain food products in the USA and several countries in Central and South America, the Middle East, Africa, Asia, and Australia. 17 Related Substances Alitame.

Comments

The perceived intensity of sweeteners relative to sucrose depends upon their concentration, temperature of tasting, and pH, and on the flavor and texture of the product concerned. Intense sweetening agents will not replace the bulk, textural, or preservative characteristics of sugar, if sugar is removed from a formulation. Synergistic effects for combinations of sweeteners have been reported, e.g. acesulfame potassium with aspartame or sodium cyclamate; see also Aspartame. A ternary combination of sweeteners that includes acesulfame potassium and sodium saccharin has a greater decrease in sweetness upon repeated tasting than other combinations.(10) Note that free acesulfame acid is not suitable for use as a sweetener. A specification for acesulfame potassium is contained in the Food Chemicals Codex (FCC).(11) 19 Specific References 1 Kloesel L. Sugar substitutes. Int J Pharm Compound 2000; 4(2): 86–87. 2 Schmidt R et al. Evaluating toothpaste sweetening. Cosmet Toilet 2000; 115: 49–53. Acetic Acid, Glacial 5 3 4 5 6 7 8 9 10 Wilson R, ed. Sweeteners, 3rd edn. Oxford, UK: Blackwell Publishing, 2007; 3–19. Mullarney MP et al. The powder flow and compact mechanical properties of sucrose and three high-intensity sweeteners used in chewable tablets. Int J Pharm 2003; 257: 227–236. Birch GG et al. Apparent specific volumes and tastes of cyclamates, other sulfamates, saccharins and acesulfame sweeteners. Food Chem 2004; 84: 429–435. Hutteau F et al. Physiochemical and psychophysical characteristics of binary mixtures of bulk and intense sweeteners. Food Chem 1998; 63(1): 9–16. Lipinski G-WvR, Huddart BE. Acesulfame K. Chem Ind 1983; 11: 427– 432. Shetty K, ed. Functional Foods and Biotechnology. Boca Raton, FL: CRC Press, 2007; 327–344. FAO/WHO. Evaluation of certain food additives and contaminants. Thirty-seventh report of the joint FAO/WHO expert committee on food additives. World Health Organ Tech Rep Ser 1991; No. 806. Schiffman SS et al. Effect of repeated presentation on sweetness intensity of binary and tertiary mixtures of sweetness. Chem Senses 2003; 28: 219–229. 11 Food Chemicals Codex, 6th edn. Bethesda, MD: United States Pharmacopeia, 2008; 9.

General References

Anonymous. Artificial sweetners. Can Pharm J 1996; 129: 22. Lipinski G-WvR, Lu¨ck E. Acesulfame K: a new sweetener for oral cosmetics. Manuf Chem 1981; 52(5): 37. Marie S. Sweeteners. Smith J, ed. Food Additives User’s Handbook. Glasgow: Blackie, 1991; 47–74. Celanese Corp. Nutrinova technical literature: The Sunett guide to sweetness, 2008.

Author

BA Johnson.

Date of Revision

26 February 2009.