Желатин

Описание

Gelatin does not occur in nature as such, but is derived by hydrolysis of collagen, the chief protein component in connective tissues of the animal body. The major sources of collagen are cattle hides, pig skins and bones. The resulting gelatin is of two types commonly designated A and B, depending upon which of two processes are used to convert the collagen into gelatin. Type A gelatin is derived primarily from pig skin by acid processing; it has an isoelectric point between pH 7 and pH 9. Type B is from cattle hides and bones by alkaline or lime processing and has an isoelectric point between pH 4.7 and pH 5.1.

Физические свойства

Gelatin is colorless or slightly yellow, transparent, brittle, practically odorless, tasteless, presenting as sheets, flakes or a coarse powder. On being warmed, gelatin disperses into the water resulting in a stable suspension. Water solutions of gelatin will form a reversible gel if cooled below the specific gel point of gelatin. The gel point is dependent on the source of the raw material. Gelatin extracted from the tissues of warm-blooded animals will have a gel point in the range of 30°C - 35°C. Gelatin extracted from the skin of cold-water ocean fish will have a gel point in the range of 5°C - 10°C. Gelatin is soluble in aqueous solutions of polyhydric alcohols such as glycerin and propylene glycol.

Химические свойства

white to slightly yellow powder, also knownas glutin,is a protein found in many animal tissues including skin, cartilage, horn, and bone. Gelatin is used in leather dressings, in photography, in metallurgy, in the plastics industry, and in pharmaceuticals.

Вхождение

Gelatin is a protein obtained by partial hydrolysis of collagen, the chief protein component in skin, bones, hides, and white connective tissues of the animal body. Type A gelatin is produced by acid processing of collagenous raw material; type B is produced by alkaline or lime processing. Because it is obtained from collagen by a controlled partial hydrolysis and does not exist in nature, gelatin is classified as a derived protein. Animal glue and gelatin hydrolysate, sometimes referred to as liquid protein, are products obtained by a more complete hydrolysis of collagen and can thus be considered as containing lower molecular-weight fractions of gelatin.

Использование

gelatin is used as a natural sealant against moisture loss and as a formulation thickener. The films produced by gelatin are tacky when moist and hard, and brittle when dry. It is obtained by the partial hydrolysis of mature collagen derived from the skin, connective tissue, and bones of animals. It does not have the waterbinding ability of soluble collagen.

Общее описание

Gelatin, NF, is a protein obtained by the partial hydrolysis of collagen, an albuminoid found in bones, skin, tendons, cartilage, hoofs, and other animal tissues. Gelatin is used in the preparation of capsules, in the coating of tablets, and, with glycerin, as a vehicle for suppositories. It has also been used as a vehicle when slow absorption is desired for drugs.

Сельскохозяйственное использование

Gelatin is a colorless or pale yellow water-soluble protein obtained by boiling collagen with water and evaporating the water. It is an ingredient in jellies and baked goods. It is also used to make medicinal capsules, and coat photographic films.

Профиль безопасности

An experimental teratogen. Experimental reproductive effects. When heated to decomposition it emits acrid smoke and irritating fumes.

Безопасность

Gelatin is widely used in a variety of pharmaceutical formulations, including oral and parenteral products.
In general, when used in oral formulations gelatin may be regarded as a nontoxic and nonirritant material. However, there have been rare reports of gelatin capsules adhering to the esophageal lining, which may cause local irritation. Hypersensitivity reactions, including serious anaphylactoid reactions, have been reported following the use of gelatin in parenteral products.
There have been concerns over the potential spread of BSE/TSE infections through bovine derived products. However, the risk of such contamination of medicines is extremely low.
LD50 (rat, oral): 5 g/kg
TDLo (mouse, IP): 700 mg/kg

хранилище

Dry gelatin is stable in air. Aqueous gelatin solutions are also stable for long periods if stored under cool conditions but they are subject to bacterial degradation. At temperatures above about 50°C, aqueous gelatin solutions may undergo slow depolymerization and a reduction in gel strength may occur on resetting. Depolymerization becomes more rapid at temperatures above 65°C, and gel strength may be reduced by half when a solution is heated at 80°C for 1 hour. The rate and extent of depolymerization depends on the molecular weight of the gelatin, with a lower-molecular-weight material decomposing more rapidly.Dry gelatin is stable in air. Aqueous gelatin solutions are also stable for long periods if stored under cool conditions but they are subject to bacterial degradation.(4) At temperatures above about 50°C, aqueous gelatin solutions may undergo slow depolymerization and a reduction in gel strength may occur on resetting. Depolymerization becomes more rapid at temperatures above 65°C, and gel strength may be reduced by half when a solution is heated at 80°C for 1 hour. The rate and extent of depolymerization depends on the molecular weight of the gelatin, with a lower-molecular-weight material decomposing more rapidly.
Gelatin may be sterilized by dry heat.
The bulk material should be stored in an airtight container in a cool, well-ventilated and dry place.

Несовместимости

Gelatin is an amphoteric material and will react with both acids and bases. It is also a protein and thus exhibits chemical properties characteristic of such materials; for example, gelatin may be hydrolyzed by most proteolytic systems to yield its amino acid components.
Gelatin will also react with aldehydes and aldehydic sugars, anionic and cationic polymers, electrolytes, metal ions, plasticizers, preservatives, strong oxidizers, and surfactants. It is precipitated by alcohols, chloroform, ether, mercury salts, and tannic acid. Gels can be liquefied by bacteria unless preserved.
Some of these interactions are exploited to favorably alter the physical properties of gelatin: for example, gelatin is mixed with a plasticizer, such as glycerin, to produce soft gelatin capsules and suppositories; gelatin is treated with formaldehyde to produce gastroresistance.

Регуляторный статус

GRAS listed. Included in the FDA Inactive Ingredients Database (dental preparations; inhalations; injections; oral capsules, pastilles, solutions, syrups and tablets; topical and vaginal preparations). Included in medicines licensed in the UK, Europe, and Japan. Included in the Canadian List of Acceptable Non-medicinal Ingredients.