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Acacia and other Gums
Martindales 24^th.
Compiled by Ivor Hughes

ACACIA and other Gums
Acacia (B.P.). Gum Acacia; Gum Arabic; Gummi Africanum; Gummi Mimosae; Gomme Arabique; Gomme de Senegal.

Foreign Pharmacopoeias:
In all pharmacopoeias examined, except Ind. which specifies Indian Acacia (from A. arabica).

A dried exudation from the stem and branches of Acacia senegal (Leguminosae), and some other species of Acacia.

Odourless, nearly colourless, or pale yellow, rounded or ovoid, brittle tears with a bland mucilaginous taste. The tears are opaque from the presence of numerous minute fissures and are often broken into angular fragments. Protect from light.

Soluble almost entirely 1 in 1 of water; insoluble in alcohol. Solutions are sterilised by autoclaving. Incompatible with alcohol, bismuth sub nitrate, borax, ferric salts, calomel, lead subacetate, and with acids unless well diluted.

Uses.
Intravenous injection of sodium chloride and acacia has been employed to increase the blood volume and raise blood pressure in severe hemorrhage and shock, but it causes a decrease in serum proteins; it has been replaced by blood transfusions or blood plasma substitutes.

Intravenous acacia has also been employed as a diuretic in the treatment of nephrotic oedema. It was often found successful for this purpose but is now known to exert a deleterious effect on hepatic functioning and its use is condemned.

Powdered acacia is used as an emulsifying agent for oils, the usual proportions being about 1 of gum to 4 of fixed oil or 2 of a volatile oil; in the case of resinous tinctures, Mucilage of Acacia may be used in the proportion of not less than 1 in 16 of the finished mixture. It is also used as a pill excipient, and as a suspending agent in mixtures containing insoluble powders.

Mucilage of Acacia (B.P.). Mucilago Acaciae; Mucil. Acac.; Gummischleim.
Acacia 4 by wt, rinsed to remove dust, and dissolved in chloroform water 6 by vol. This quantity measures about 83/4. It should be recently prepared.

Jap. P. and U.S.P. have acacia 35 g., benzoic acid 200 mg., water to 100 ml.

Most other pharmacopoeias include acacia mucilage's of varying strengths, usually including a preservative such as sodium benzoate or methyl hydroxybenzoate.

Potion Gommeuse (Fr. P.). Julep Gommeux; Potio Gummosa.
Acacia powder 1, syrup 3, orange-flower water 1, water to 15.
Similar preparations are included in Chil. P., Span. P., and Swiss P.

Pulv. Acac. et Trag.(B.P.C. 1949). Powder of Acacia and Tragacanth; Compound Powder of Acacia. Acacia 1 and tragacanth 1. A useful pill excipient.

Syr. Acac. (B.P.C. 1934). Acacia Syrup; Sirop de Gomme; Gummisirup; Jarabe de Goma.
Mucilage of acacia 25 ml., syrup to 100 ml.; it should be freshly prepared. A demulcent for use in cough mixtures.
Dose: 4 to 16 ml. (60 to 240 minims).

Similar syrups are included in Fr.P., Span.P., Swiss P. and Ind. P.C., U.S.P. has acacia 70 g., sodium benzoate 100 mg., vanilla tincture 0.5 ml., sucrose 80 g., water to 100 ml. Ind. P. has Indian acacia 10 g., sodium benzoate 700 mg., tincture of orange 0�5 ml., sucrose 80 g., water to 100 ml.

Gummi Arabicum Desenzymatum (Cz. P., Span. P., Swiss P.) is obtained by evaporating the mucilage and powdering the residue; oxidases are thus destroyed.

Ceratonia (B.P.C. 1949). Cerat. ; Ceratonia Gum; Carob Gum.
The endosperms separated from the seeds of the locust bean tree, Ceratonia siliqua (Leguminosae). Powdered ceratonia is sometimes known as Cheshire gum. Protect from moisture.

Uses. It is used as a substitute for tragacanth. A mucilage similar to mucilage of tragacanth may be prepared by boiling 1 to 1.5% of powdered ceratonia with water.

As a thickening agent for pharmaceuticals and foods it is said to be about 5 times as effective as starch and twice as effective as gum tragacanth. (C. Griffiths, Mfg Chem., 1949, 20, 321.)

Mucilage of Ceratonia.
Powdered ceratonia 1 g., glycerin 3 ml., benzoic acid 150 mg., triturate and add water to 80 ml.; heat the mixture on a water-bath for 30 minutes. The mucilage is somewhat more viscid than Mucilage of Tragacanth. Heating is necessary to inactivate the enzyme present in ceratonia which, if not destroyed, causes loss of viscosity by hydrolysis. Various other formulae for ceratonia preparations are given.-W. A. Knight and M. M. Dowsett, Pharm. J., i/1936, 35.

Guar Gum. Guar Flour; Jaguar Gum.

The ground endosperms of the seeds of Cyanopsis tetragonaloba or of C. proraloides (Compositae). A white to greyish-white powder with a bland taste. It is dispersible in hot or cold water to form colloidal solutions.

GUAR MUCILAGES.
A 1% mucilage is comparable in viscosity to Mucilage of Acacia, and a 3% mucilage is comparable to Mucilage of Tragacanth. Benzoic acid 0.02% is a suitable preservative. Guar mucilage is a good suspending agent for oils, but not for heavy powders. A 1% mucilage may be used as a pill excipient, tablet binding agent, or gelling agent, but it is not suitable for the preparation of emulsions. It is compatible with acids, solutions of electrolytes, and heavy metal salts, but incompatible with strong alkalis, alcohol, and acetone.-G. E. Osborne and C. O. Lee, Bull. nat. Formul. Comm., 1951, 19,4.

TABLET BINDER AND DISINTEGRATING AGENT.
A 1.5% guar mucilage was satisfactory for digitalis, lactose, sulphathiazole, and thyroid tablets.  L. E. Eatherton et al., Drug Standards, 1955, 23, 42.

BASE FOR MEDICATED JELLIES.
Guar gum 2%, glycerin (or propylene glycol) 10%, alkyl p-hydroxybenzoate 0.17%, in water. The glycerin or propylene glycol was mixed with the water before dispersing the gum in it, or used to wet the gum before adding it to the water. Liquefaction occurred in jellies containing 1 %, of triethanolamine, ephedrine sulphate, or lactic acid, or 1.5% of mepyramine maleate.
H. H. Hutchins and R. E. Singiser, J. Amer. pharm. Ass., Pract. Pharm. Edn, 1955, 16, 226.

Sterculia (B.P.C.). Stercul.; Sterculia Gum; Indian Gum; Indian Tragacanth; Karaya Gum.
The dried gummy exudation from Sterculia urens and other species of Sterculia (Sterculiaceae)

Foreign Pharmacopoeias: In Dan., Nor., and Swed. Also in U.S.N.F. which allows also the gum from Cochlospermum gossypium and other species of Cochlospermum (Bixaceae).

Irregular or vermiform, greyish or pinkish pieces with a faint odour resembling that of acetic acid. Protect from moisture in a cool place:

Uses. Sterculia is used internally to stimulate peristalsis in the treatment of constipation. It has adhesive properties and is used in dental fixative powders. It has also been used similarly to tragacanth to prepare bases for applications, e.g. Cream of Aminacrine. It is a less efficient suspending agent than tragacanth.
It is used in industry as a thickening and suspending agent in the manufacture of lotions and pastes and various foods.

Base for Medicated Jellies.
Sterculia 5% with glycerin or propylene glycol 10% w/w in water. A preservative (e.g. 0�17% of alkyl p-hydroxybenzoates) is required. Incompatible with crystal violet (1%). H. H. Hutchins and R. E. Singiser, J. Amer. pharm. Ass., Pract. Pharm. Edn, 1955, 16, 226.

PROPRIETARY PREPARATIONS CONTAINING STERCULIA
Aperigran (Fletcher, Fletcher & Co.). Flavoured granules containing sterculia 30%. For constipation. Dose: children 1 to 2 heaped teaspoonfuls daily, adults 2 to 3 heaped teaspoonfuls daily. Aperigran Forte. Granules containing, in addition, phenolphthalein 1 %. 

Tragacanth (B.P.). Trag.; Gum Dragon; Gum Tragacanth; Gomme Adragante; Traganth; Tragacanto.

Foreign Pharmacopoeias: In all pharmacopoeias examined.

The dried gummy exudation from Astragalus gummifer and some other species of Astragalus (Leguminosae). It is known in commerce as Persian tragacanth and occurs as thin, flattened, more or less curved, ribbon-like flakes which are odourless and almost tasteless.

Partly soluble in water, in which it swells to a homogeneous, adhesive, gelatinous mass; insoluble in alcohol. Store in a dry place.

Hog gum, from species of Prunus, and sterculia gum are used in industry as substitutes for tragacanth.

Uses. Tragacanth, in the form of Mucilage of Tragacanth or Compound Powder of Tragacanth, is widely used to suspend heavy insoluble powders and many resinous tinctures. A mixture of Mucilage of Tragacanth and Mucilage of Acacia is more effective for some resinous tinctures, especially if salts are present. In lotions for external use Mucilage of Tragacanth is preferable to Mucilage of Acacia as a suspending agent. Tragacanth is added to emulsions prepared with acacia, in order to retard creaming, and is used as a thickening agent in the manufacture of creams, jellies, and pastes.

Linimentum Exsiccans (Bassorin Paste) is prepared by shaking vigorously in a wide-mouthed bottle, 5% of tragacanth powder, 10% of alcohol, and 70% of water, and then adding 2% of glycerin, and water to 100%; it dries on the skin as a transparent film, easily removed by washing. It has been used as a basis for medicaments such as ichthammol, salicylic acid, resorcinol, and sulphur.

Gelanthum (Unna's jelly) is a similar preparation and contains tragacanth, gelatin, glycerin, and water with a little thymol. Tragacanth is also used as the basis of lubricants for catheters and surgical instruments and in powder form as an adhesive for dentures.

Tragacanth is used, but sparingly, as an excipient for pills containing no binding ingredient; excess of tragacanth produces an elastic mass difficult to convert into spherical form, and not more than 5 % should be added and the pills massed with Syrup of Liquid Glucose.

Powder of Acacia and Tragacanth, B.P.C. 1949, and Glycerin of Tragacanth, B.P.C. 1949, in minimum amounts are sometimes used for this purpose; the mass should be well kneaded. Glucanth is a pill excipient containing 1 part of tragacanth, 1 part of water, and 4 parts of Syrup of Liquid Glucose.

Glycerins
Glycanth (A.P.F.). Water-soluble Base; Glycerin and Tragacanth Base. Mix tragacanth 12 gr. with glycerin 140 gr., add water to 500 gr., boil for one minute, cool and add water to 500 gr. A convenient vehicle for application of water-soluble drugs such as adrenaline hydrochloride, ephedrine hydrochloride, aminacrine hydrochloride, hydroxyquinoline, crystal violet and brilliant green, to skin, mucosae or denuded surfaces.

Glycer. Trag. (B.P.C. 1949). Glycerin of Tragacanth.
Tragacanth 20 g., glycerin 60 ml., and water 20 ml. A pill excipient; it must be used sparingly.

Lotion
Lot. Trag. (B.P.C. 1934). Tragacanth Lotion; Emollient Lotion.
Tragacanth 24 gr., spirit of chloroform 90 m., tincture of tolu 90 in., Cologne spirit 120 m., glycerin 90 m., water to 10 fl. oz.

Lubrication jellies
Compound Paste of Tragacanth (B.P.C.). Past. Trag. Co. Catheter Lubricant; Lubricating Jelly.
Tragacanth 2.29 g., glycerin 20 ml., alcohol (95%) 2.5 ml., phenylmercuric nitrate 11.4 mg., water to 100 ml. It is sterilised by maintaining the whole of the paste at a temperature of 98� to 100� for 30 minutes.

Glycanth of Phenylmercuric Nitrate (A.P.F.) is glycanth (A.P.F.) containing 0.01 % of phenylmercuric nitrate, sterilised by heating at 100� for 30 minutes. It is used as a catheter lubricant.

Past. Glycer. et Hydrarg. Perchlorid. (St. Bart's Hosp.). Lubricating Jelly.
Tragacanth powder 9 gr., glycerin 96 m., solution of mercuric chloride, 1 in 2000, to 1 fl. oz., coloured pale blue with methylene blue.

Past. Hydrarg. Oxycyanid. (Lond. Hosp.).
Tragacanth 192 gr., mercuric oxycyanide 24 gr., glycerin 4 fl. oz., water to 20 fl. oz. Sterilised.

Past. Hydrarg. Oxycyanid. Co. (Cape Hosp.). Catheter Lubricant.
Powdered tragacanth 9 gr., mercuric oxycyanide 1 gr., glycerin 60 gr., water to 480 gr.

Pasta Lubricans (Guy's Hosp.). Catheter Lubricant; Diathermy Jelly.
Tragacanth 7 5 gr., glycerin 60 m., methyl hydroxybenzoate 1 Kr., water 420 m.

Pasta Lubricans et Hydrargyri Perchloridi (Guy's Hosp.). Rectal Lubricant.
Tragacanth 7.5 gr., mercuric chloride 1.25 gr., glycerin 60 m., water 420 m.; it is coloured blue with indigo carmine.

MUCILAGES
Mucilage of Tragacanth (B.P.). Mucilago Tragacanthae; Mucil. Trag.
Tragacanth 1.25g., alcohol (90%) 2.5 ml., chloroform water to 100 ml.

Egyp. P. and Ind. P. have the same formula. Mucilage made from whole gum has a much higher viscosity than that made from powdered gum and, if not heated, increases in viscosity on keeping. There is no advantage m adopting any particular method of preparation when the mucilage is to be diluted and used for its power of suspending an insoluble powder.
H. Brindle and H. Burlinson, Quart. J. Pharm., 1934, 7, 492. See also G. Middleton, ibid., 1936, 9,493, 506.

PRESERVATIVES
Mucilage of tragacanth reduces the bactericidal action of many common preservatives such as chlorbutol, benzalkonium chloride, phenol, phenylmercuric acetate, thiomersal, and alkyl hydroxybenzoates.  P.C. Eistnan, Pharm. J., ii/1956, 88; idem, J. Amer. pharm. Ass., Sci. Edn, 1957, 46, 144.

Tragacanth Mucilage (U.S.N.F.).
Tragacanth 6, benzoic acid 0�2, glycerin 18, water to 100, all by wt.
Fr. P, and Span. P. have 10% w/w in water; Swed. P. has 1% with methyl p-hydroxybenzoate 0�1% and glycerin 5% in water, all w/w.

Powder
Compound Powder of Tragacanth (B.P.).
Pulv. Trag. Co. Tragacanth 15, acacia 20, starch 20, and sucrose 45.
Ind. P. has same formula; Egyp. P. has starch 15 and sucrose 50.
Dose: 0.6 to 4 g. (10 to 60 grains).
It is used as a suspending agent-10 gr. to 1 fl. oz. The presence of acacia in compound tragacanth powder results in a considerable reduction in the viscosity and suspending power of the tragacanth consituent. J. M. Rowson, Quart. J. Pharm., 1937, 404.

STORAGE IN THE TROPICS.
Compound Powder of Tragacanth deteriorates rapidly under tropical conditions. Deterioration may be prevented by drying the freshly prepared powder at 100� and storing in small sealed bottles. When the bottles have ,cc, n opened t he contents will remain m good condition for only a few weeks. Alternatively, a stable preparation may be obtained by replacing the sucrose with acacia and adding 0.1% of saccharin sodium.  A. B. Elliott, Malay. Pharm. J., 1956, 5, 112.

The Tragacanth image is from Denstons Pharmacognosy.
Related Monographs : Acacia B.P.  also, Tragacanth B.P.

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