Gelatin

• BPGelatin
• JPGelatin
• Ph. Eur.Gelatin
• USP–NFGelatin

Byco; Cryogel; gelatina; gelatine; Instagel; Solugel

Gelatin (a mixture of purified proteins obtained by partial hydrolysis of animal collagen) · [9000-70-8]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Binder, Coating agent, film former, Gelling agent, viscosity modifier

Typical concentrations: — · Dosage forms: Solid, Semi-solid

Gelatin is the main shell-forming material of hard and soft capsules. It is also used in microencapsulation, as a tablet binder (applied as a warm aqueous solution in wet granulation), in tablet coating, as a gelling and viscosity-increasing agent, in glycerinated gelatin suppository and pastille bases, and as a stabiliser in vaccines. Absorbable gelatin sponges and modified (succinylated) gelatin plasma expanders are medical uses of the material. It is widely used in foods and confectionery.

A light amber to faintly yellow, vitreous, brittle solid supplied as sheets, flakes, granules or a coarse powder; practically odourless and tasteless. Type A gelatin is obtained by acid treatment and Type B by alkaline treatment of collagen; the two types differ in isoelectric point. Grades are characterised by gel strength (Bloom value) and viscosity.

Isoelectric point

Type A about 7–9; Type B about 4.7–5.4

Gel strength (Bloom)

about 50–300 g, depending on grade

Gelling temperature

solutions set to a gel on cooling below about 35–40 °C

Solubility

swells and absorbs 5–10 times its weight of cold water; soluble in hot water, glycerin, acids and alkalis; practically insoluble in ethanol, chloroform and ether

Loss on drying

not more than 15% (USP-NF)

Dry gelatin is stable in air. Aqueous solutions are stable for long periods if kept cool, but readily support bacterial growth; prolonged heating above about 50 °C causes depolymerisation and loss of gel strength. Store in an airtight container in a cool, dry place.

Gelatin is amphoteric and reacts with both acids and bases. It is cross-linked by aldehydes (including traces from excipients and packaging) and by some reducing sugars, which lowers the solubility of capsule shells. It can also interact with anionic and cationic polymers, electrolytes, metal ions, surfactants and preservatives, and is precipitated by ethanol, tannic acid and mercury salts.

Obtained by partial hydrolysis of collagen from the skins, connective tissue and bones of pigs, cattle or fish. Acid pre-treatment (mainly of pig skin) gives Type A gelatin, and prolonged alkaline (lime) treatment of bovine bone or hide gives Type B. The gelatin is extracted with hot water, filtered, concentrated, dried and milled.

Non-toxic when taken orally. Hypersensitivity reactions, including anaphylaxis, have been reported, particularly to gelatin in vaccines and to gelatin-based plasma expanders. The risk of transmitting animal spongiform encephalopathies is controlled through sourcing and processing requirements.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended; avoid inhaling the dust.

GRAS listed. Included in the FDA Inactive Ingredient Database (dental, intramuscular, intravenous, oral, topical and vaginal preparations) and in parenteral and non-parenteral medicines licensed in Europe. In Europe gelatin is treated as a food rather than a food additive. Manufacturers must comply with the European requirements for minimising the risk of TSE transmission.

Collagen; gelatin hydrolysate; succinylated gelatin; hypromellose and pullulan (non-animal capsule shell materials).

Cross-linking of gelatin capsules on storage can slow dissolution; the pharmacopoeias allow a second dissolution test with added enzymes (pepsin or pancreatin) for this reason. Animal origin matters for patients who avoid pork or bovine products for religious or dietary reasons.