Xanthan gum

• BPXanthan Gum
• Ph. Eur.Xanthan Gum
• USP–NFXanthan Gum

corn sugar gum; Keltrol; polysaccharide B-1459; Rhodigel; Vanzan NF; Xantural; xanthani gummi; E415

High-molecular-weight anionic polysaccharide made up of glucose, mannose and glucuronic acid units, present as the sodium, potassium or calcium salt · [11138-66-2]

(C35H49O29)n · ≈ 2 × 10⁶

Gelling agent, viscosity modifier

Typical concentrations: q.s. · Dosage forms: Liquid, Semi-solid

Widely used in oral and topical products as a suspending, stabilising, thickening and emulsion-stabilising agent, and in hydrophilic matrix tablets to control drug release. Its solutions are highly pseudoplastic, so they are viscous at rest but pour and spread easily, and they keep their viscosity over a wide range of pH and temperature. Typical concentrations as a suspending, stabilising or thickening agent are about 0.1–1% w/v; higher levels are used in matrix tablets.

A cream- or white-coloured, odourless, free-flowing fine powder.

Solubility

soluble in cold and hot water; practically insoluble in ethanol and ether

Viscosity

≈ 1200–1600 mPa s (1% w/v aqueous solution, 25 °C); strongly shear-thinning

pH

about 6–8 (1% w/v aqueous solution)

Pyruvic acid content

not less than 1.5% (Ph. Eur.)

A stable material. Aqueous solutions are stable over a wide pH range (about 3–12) and their viscosity changes little with temperature, although they are most stable at pH 4–10 and moderate temperatures. Solutions should be preserved against microbial spoilage. Store in a well-closed container in a cool, dry place.

Being anionic, it can precipitate with some cationic surfactants, polymers and preservatives. It is also incompatible with strong oxidising agents. It is compatible with most other suspending agents and with high concentrations of many salts.

Produced by aerobic fermentation of a carbohydrate such as glucose or sucrose by the bacterium Xanthomonas campestris. The gum is recovered from the broth by precipitation with isopropyl alcohol, then dried and milled.

Widely used in foods and medicines and regarded as non-toxic and non-irritant at the levels used. Large oral amounts can cause flatulence and loose stools. JECFA has allocated an ADI 'not specified'. Xanthan-based thickeners have been associated with necrotising enterocolitis in premature infants, and the FDA has advised against their use in that group.

Observe normal precautions for the quantity handled. Avoid generating dust; eye protection and a dust mask are recommended. Spilled powder becomes very slippery when wet.

Approved as a food additive in the USA and accepted in Europe as a food additive (E415). Included in the FDA Inactive Ingredient Database (oral solutions, suspensions and tablets; rectal and topical preparations) and in non-parenteral medicines licensed in Europe.

Carrageenan; guar gum; locust bean gum; sodium alginate; tragacanth.

To avoid lumps, disperse the powder in water with vigorous stirring or pre-wet it with glycerin, propylene glycol or ethanol before adding water. It shows synergistic viscosity increases with galactomannans such as guar and locust bean gum.