Sorbitol

• BPSorbitol
• JPD-Sorbitol
• Ph. Eur.Sorbitol
• USP–NFSorbitol

D-Glucitol; glucitol; sorbitolum; Liponic; Neosorb; Parteck SI; Sorbifin; Sorbogem; E420

D-Glucitol · [50-70-4]

UNII 506T60A25R · PubChem CID 5780

C6H14O6 · 182.17

Sweetening agent, Solvent, humectant

Typical concentrations: 20–35% oral solutions · Dosage forms: Liquid

Sorbitol is used as a diluent in tablets made by wet granulation or direct compression (especially chewable and lozenge-type tablets), as a sweetening agent, humectant and plasticiser, and as a vehicle in sugar-free liquids. Typical concentrations: tablet binder and filler 25–90%; humectant 3–15%; moisture-control agent in tablets 3–15%; oral solutions 20–35%; oral suspensions up to 70% (as sorbitol solution); plasticiser for gelatin and cellulose films 5–20%; to prevent crystallisation around bottle caps 15–30%; toothpastes 20–60%; topical emulsions 2–18%; intramuscular injections 10–25%.

An odourless, white or almost colourless, crystalline, hygroscopic powder, granules or flakes with a pleasant, cooling, sweet taste; its sweetness is about 50–60% of that of sucrose. Several crystalline polymorphs and an amorphous form exist; the stable γ-form is used in most direct-compression grades.

Melting point

about 110–112 °C (anhydrous γ-form); metastable forms melt lower (about 93–100 °C)

Solubility

very soluble in water (about 1 in 0.5); slightly soluble in ethanol; practically insoluble in chloroform and ether

Relative sweetness

about 50–60% of sucrose

Heat of solution

negative (endothermic), giving a cooling sensation in the mouth

Density

true density about 1.49 g/cm³

Chemically relatively inert and compatible with most excipients. It is stable in air, does not darken or decompose at elevated temperatures or in the presence of amines, and is not fermented by many micro-organisms, although solutions may support mould growth if unpreserved. It is hygroscopic and should be stored in an airtight container in a cool, dry place.

Sorbitol forms water-soluble chelates with many divalent and trivalent metal ions in strongly acidic and alkaline conditions. Adding liquid polyethylene glycols to sorbitol solution with vigorous stirring produces a waxy, water-soluble gel. It may discolour in the presence of iron oxide.

Manufactured by catalytic hydrogenation of D-glucose (obtained from maize or wheat starch) under high pressure, followed by purification and crystallisation or concentration to sorbitol solution.

Sorbitol is slowly and incompletely absorbed from the gut and has an osmotic laxative effect; oral intake of more than about 20 g daily in adults may cause diarrhoea, flatulence and abdominal discomfort, and smaller amounts can affect children. It is metabolised to fructose and should be avoided in hereditary fructose intolerance. It is not cariogenic and is used in products for diabetics, although it still provides energy.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended.

GRAS listed. Accepted as a food additive in Europe (E420); foods containing more than 10% added polyols must carry a warning about laxative effects. Included in the FDA Inactive Ingredient Database (dental, inhalation, IM, IV and other injections, oral capsules, solutions, suspensions, syrups and tablets, rectal, topical and vaginal preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Sorbitol solution 70%; sorbitol sorbitan solution; mannitol; maltitol; xylitol.

Direct-compression sorbitol grades give hard tablets with a pleasant mouthfeel, but the material is hygroscopic, so manufacture should take place below about 50% RH and the product be packaged with moisture protection. The total daily sorbitol dose delivered by a product should be considered, particularly for paediatric liquids, because of its laxative effect.