Трагакантовая камедь

Химические свойства

Tragacanth gum occurs as flattened, lamellated, frequently curved fragments, or as straight or spirally twisted linear pieces from 0.5–2.5mm in thickness; it may also be obtained in a powdered form. White to yellowish in color, tragacanth is a translucent, odorless substance, with an insipid mucilaginous taste.

Физические свойства

As collected, tragacanth is white to weak yellow, translucent; horny in texture, having a short fracture. It is rendered more easily pulverizable if heated to 50°C. Powdered tragacanth is white to yellowish white. Gum tragacanth swells in cold water to give extremely viscous colloidal solutions, probably the most viscous of all the plant gums.

Использование

tragacanth gum is an effective emulsifying agent, binder, film former, and viscosity controller, it is also used as a stabilizing ingredient in lotions. Tragacanth gum is derived from the resin of the Astragalus gummifer shrub.

Методы производства

Tragacanth gum is the air-dried gum obtained from Astragalus gummifer Labillardie`re and other species of Astragalus grown principally in Iran, Syria, and Turkey. A low-quality gum is obtained by collecting the natural air-dried exudate from Astragalus bushes. A higher-grade material is obtained by making incisions in the trunk and branches of the bush, which are held open with variously sized wooden pegs. The exudate is left to drain from the incision and dry naturally in the air before being collected. The size and position of the wooden wedges determine the physical form of the exudate, while the drying conditions determine the color of the gum. After collection, the tragacanth gum is sorted by hand into various grades, such as ribbons or flakes.

Общее описание

Tragacanth is a gum commonly found in the sap of various Middle Eastern legumes. It is commonly used as freezing-embedding medium for tissue preservation.

Фармацевтические приложения

Tragacanth gum is used as an emulsifying and suspending agent in a variety of pharmaceutical formulations. It is used in creams, gels, and emulsions at various concentrations according to the application of the formulation and the grade of gum used.
Tragacanth gum is also used similarly in cosmetics and food products, and has been used as a diluent in tablet formulations.

Профиль безопасности

Mildly toxic by ingestion. A mild allergen. A skin and eye irritant. Combustible when exposed to heat or flame. When heated to decomposition it emits acrid smoke and irritating fumes.

Безопасность

Tragacanth has been used for many years in oral pharmaceutical formulations and food products, and is generally regarded as an essentially nontoxic material. Tragacanth has been shown to be noncarcinogenic. However, hypersensitivity reactions, which are occasionaly severe, have been reported following ingestion of products containing tragacanth. Contact dermatitis has also been reported following the topical use of tragacanth formulations.
The WHO has not specified an acceptable daily intake for tragacanth gum, as the daily intake necessary to achieve a desired effect, and its background levels in food, were not considered to be a hazard to health.
LD50 (hamster, oral): 8.8 g/kg
LD50 (mouse, oral): 10 g/kg
LD50 (rabbit, oral): 7.2 g/kg
LD50 (rat, oral): 16.4 g/kg

хранилище

Both the flaked and powdered forms of tragacanth are stable. Tragacanth gels are liable to exhibit microbial contamination with enterobacterial species, and stock solutions should therefore contain suitable antimicrobial preservatives. In emulsions, glycerin or propylene glycol are used as preservatives; in gel formulations, tragacanth is usually preserved with either 0.1% w/v benzoic acid or sodium benzoate. A combination of 0.17% w/v methylparaben and 0.03% w/v propylparaben is also an effective preservative for tragacanth gels. Gels may be sterilized by autoclaving. Sterilization by gamma irradiation causes a marked reduction in the viscosity of tragacanth dispersions.
Tragacanth dispersions are most stable at pH 4–8, although stability is satisfactory at higher pH or as low as pH 2. The bulk material should be stored in an airtight container in a cool, dry place.

Несовместимости

At pH 7, tragacanth has been reported to considerably reduce the efficacy of the antimicrobial preservatives benzalkonium chloride, chlorobutanol, and methylparaben, and to a lesser extent that of phenol and phenylmercuric acetate. However, at pH < 5 tragacanth was reported to have no adverse effects on the preservative efficacy of benzoic acid, chlorobutanol, or methylparaben.
The addition of strong mineral and organic acids can reduce the viscosity of tragacanth dispersions. Viscosity may also be reduced by the addition of alkali or sodium chloride, particularly if the dispersion is heated. Tragacanth is compatible with relatively high salt concentrations and most other natural and synthetic suspending agents such as acacia, carboxymethylcellulose, starch, and sucrose. Ayellow colored, stringy, precipitate is formed with 10% w/v ferric chloride solution.

Регуляторный статус

GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (buccal/ sublingual tablets, oral powders, suspensions, syrups, and tablets). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.