Rhei Radix, B.P. Rhubarb Root.

Rhubarb (Rheum, U.S.P.) is the rhizome of Rheum palmatum, Linn., R. officinale, Baill. (N.O. Polygonaceae), and probably other species, collected in China and Thibet, deprived of more or less of its cortex, and dried. The Chinese rhubarb of commerce is derived from at least two (probably three) species of Rheum growing in the mountains of the western Chinese provinces of Szechuan, Kansu, and Shensi, and the adjoining Thibetan territory. The rhizomes of the wild plants are collected, trimmed, pared, halved longitudinally if of large size, and strung on cords to dry in the sun (sun-dried), or under the roof or eaves of a house (high-dried). It is conveyed to Shanghai, whence it is imported to London. It formerly reached Europe by way of the Levant (Turkey rhubarb), India (East Indian rhubarb), or Russia (Russian rhubarb), the commercial names indicating only the route by which it reached the European market. Three varieties of Chinese rhubarb are distinguished in English commerce, viz., Shensi, Canton, and high-dried. Each variety may occur in entire rhizomes (rounds) or halved (flats). Shensi rhubarb occurs in nearly cylindrical or plano-convex pieces, often 7.5 to 15 centimetres long and 4 to 10 centimetres wide, covered with a bright yellowish-brown powder or "coat." They are hard, heavy, and compact; the fracture is uneven and the fractured surface exhibits a characteristic marbled appearance of whitish veins on a dark reddish or greyish ground ("nutmeg" fracture). The outer surface often exhibits a rhomboidal network of whitish lines and scattered star spots (fibro-vascular bundles). The section exhibits near the periphery a dark line (cambium), exterior to which are the very narrow (1 millimetre) remains of the cortex. Within the cambium is a narrow radiate normal wood, on the inner border of which occurs a circle of star-shaped spots, which commonly more or less fuse together. The aromatic odour is characteristic; the taste is bitterish and astringent. Canton rhubarb closely resembles the Shensi variety, but may be distinguished by the rinular (not veined) fracture, the more fibrous and tougher nature, and the more empyreumatic odour and taste. High-dried rhubarb may resemble either Shensi or Canton in the appearance of the fractured surface; it is distinguished by its duller, tougher coat, hardness, and strong empyreumatic odour and taste; the "rounds" are often shrunken, and exhibit the remains of a large bud at the apex with brownish patches on their outer surface. Of these varieties Shensi is the most esteemed and alone agrees with the official description; Canton is the next best, while the dark coloured, high-dried "round" is the least valued. Powdered rhubarb is characterised by its very large, rosette crystals (up to 145µ) of calcium oxalate, by its simple rounded (10 to 18µ) or compound starch grains, by its large vessels and by frequent parenchymatous cells filled with a reddish-brown, amorphous substance. It yields a very variable amount of ash, ranging usually from 7.5 to 15 per cent., but attaining in exceptional instances much higher figures. Two other varieties of rhubarb are met with in English commerce, viz., the rhizomes and roots of R. officinale, Baill. (cultivated in England), and of R. Rhaponticum, Linn. The former may be distinguished from Chinese rhubarb by its less rich colour, shrunken appearance, and parallel instead of reticulate markings. The star spots are much less developed. The latter are also shrunken in appearance, more or less distinctly pink in colour, and exhibit a diffuse circle of isolated star spots on the transverse section. Rhapontic rhubarb contains no emodin, rhein, or aloe-emodin (rhubarberone), but it contains a crystalline body, rhaponticin, the presence of which can be demonstrated by the following test:—Boil 10 grammes with 50 mils of dilute alcohol for fifteen minutes, filter, concentrate to 10 mils and shake with 10 to 15 mils of ether. On standing, a considerable quantity of a minutely crystalline deposit of rhaponticin will be formed. This test will serve to identify the drug obtained from R. Rhaponticum. The roots of these cultivated species of Rheum are easily distinguished from the rhizomes by their smaller size and distinctly radiate structure.

Constituents.—The chief constituents of rhubarb are anthraquinone derivatives, probably including alizarin. Among the substances which have been isolated from sun-dried Shensi rhubarb are cinnamic and gallic acids, tannin, rheinolic acid (C₁₇H₁₀O6, m.p. 295° to 297°), rhein, emodin, aloe-emodin, emodin mono-methylether, chrysophanic acid, and glucosides of the last five compounds. The chief purgative constituent of the drug is an amorphous non-glucosidic resin which, on hydrolysis, yields cinnamic and gallic acids, them, emodin, aloe-emodin, emodin mono- methyl- ether, chrysophanic acid, and a compound (C₁₄H₁₂O₃, m.p. 256°) which is probably trihydroxy-dihydro-anthracene. The drug also contains volatile oil, dextrose, levulose, the phytosterol verosterol, starch, calcium oxalate, and the following acids: palmitic, hexoic, stearic, oleic, linolic, and linolenic. The so-called "rheoanthra-glucoside" has been shown to be a mixture of the crystalline glucosides of anthraquinone derivatives, while "rhabarberone" and "iso-emodin" are simply impure aloe-emodin.

Action and Uses.—Rhubarb root increases the flow of saliva when chewed, and acts as a stomachic in atonic dyspepsia. Large doses are purgative; they increase peristalsis without producing inflammation of the intestines. Purgation is followed by an astringent effect owing to the tannin present. Rhubarb root is employed in diarrhoea due to irritating substances in the intestines, the after-astringent effect checking the diarrhoea. For its stomachic properties, powdered rhubarb is administered in cachets, powders, or mixtures, often with sodium bicarbonate and oil of peppermint. Small doses of compound tincture or infusion may replace the powdered drug. Pulvis Rhei Compositus and Syrupus Rhei are employed as laxatives for delicate persons and children. Preparations of rhubarb are suitable as occasional aperients, but should not be used in chronic constipation. A variable amount is absorbed, and imparts a brownish colour to the urine, which is changed to a purplish-red on the addition of alkali: symptoms of renal irritation are not, however, common.

Dose.—1 to 2 grammes (15 to 30 grains), or 2 to 6 decigrams (3 to 10 grains) for repeated administration.

PREPARATIONS.

Jalap Mixture with Rhubarb - Compound Soda Mixture - Aloes, Ipecacuanha, and Rhubarb Pills

Elixir Rhei, B.P.C.—ELIXIR OF RHUBARB. Syn.—Liquor Rhei Dulcis; Sweet Essence of Rhubarb. 1 (liquid extract) in 4.

An aperient especially suitable for children's use. Dose.—4 to 12 mils (1 to 3 fluid drachms).

Elixir Rhei et Magnesii Acetatis, C.F. and N.F.—ELIXIR OF RHUBARB AND MAGNESIUM ACETATE. Syn.—Elixir Rhei et Magnesiae; Elixir of Rhubarb and Magnesia.

Magnesia, calcined, 2; acetic acid, a sufficient quantity; liquid extract of rhubarb, 12.5; aromatic elixir, sufficient to produce 100. Dissolve the magnesia in about 15 of the acetic acid, adding more of the acid drop by drop, until the solution is neutral; then add the liquid extract and sufficient aromatic elixir to make 100. Each fluid drachm represents about 4 grains of magnesium acetate and 7 ½ grains of rhubarb. Average dose.—4 mils (1 fluid drachm).

Extractum Rhei, B.P.—EXTRACT OF RHUBARB.

Moisten rhubarb root in No. 20 powder, with alcohol (60 per cent.), set aside for forty-eight hours, then exhaust by slow percolation, recover most of the, alcohol by distillation, and evaporate the residue to a dry extract. Extract of rhubarb is prescribed in pills, generally in combination with carminatives such as oleoresin of ginger, or powdered ginger, or with aloin, podophyllin, or extract of nux vomica. Dose.—1 to 5 decigrams (2 to 8 grains).

Extractum Rhei, U.S.P.—EXTRACT OF RHUBARB, U.S.P.

Fluidextract of rhubarb, 100. Evaporated to a pilular consistence. Average dose.—2 ½ decigrams (4 grains).

Extractum Rhei Compositum, Aust. P.—COMPOUND EXTRACT OF RHUBARB.

Extract of rhubarb, 60; extract of Barbados aloes, 20; jalap resin, in powder, 10; hard soap, in powder, 10. Mix the extracts with the jalap resin, and add the powdered soap. Dose.—1 to 5 decigrams (2 to 8 grains).

Extractum Rhei Liquidum, B.P.C., Fluidextractum Rhei, U.S.P.—LIQUID EXTRACT, FLUIDEXTRACT, OF RHUBARB. 1 in 1.

Used in place of compound tincture of rhubarb for addition to stomachic mixtures. On account of the tendency of simple rhubarb preparations to cause griping it should be combined with suitable carminatives (ginger, peppermint, cardamoms). Dose.—6 to 8 decimils (0.6 to 0.8 milliliters) (10 to 30 minims).

Infusum Rhei, B.P.—INFUSION OF RHUBARB.

Rhubarb root, in thin slices, 5; distilled water, boiling, 100. Infuse the drug in the water for fifteen minutes, in a covered vessel, and strain. Infusion of rhubarb is a stomachic and mild aperient, used commonly with antacids and carminatives. Dose.—15 to 30 mils (½ to 1 fluid ounce).

Infusum Rhei Concentration, B.P.C.—CONCENTRATED INFUSION OF RHUBARB.

A product closely resembling infusion of rhubarb is obtained by diluting 1 part of this preparation with 7 parts of distilled water. Dose.—2 to 4 mils (½ to 1 fluid drachm).

Liquor Rhei Concentratus, B.P.—CONCENTRATED SOLUTION OF RHUBARB.

Rhubarb root, in No. 5 powder, 50; alcohol (20 per cent.), sufficient to produce 100. Moisten the drug with 25 of the alcohol, transfer to a percolator, set aside for three days, then percolate with 100 of the alcohol, which should be added in ten equal portions, at intervals of twelve hours; finally percolate with sufficient of the alcohol to produce the required volume. Infusum Rhei Concentratum is a more satisfactory preparation. Dose.—2 to 4 mils (½ to 1 fluid drachm).

Mistura Rhei cum Soda, B.P.C.—RHUBARB MIXTURE WITH SODA. Syn.—Mistura Rhei et Sodae; Rhubarb and Soda Mixture.

Each fluid ounce contains 5 grains of powdered rhubarb, 10 grains of sodium bicarbonate, with a sufficient quantity of caraway water. This mixture is employed as a mild laxative and antacid stomachic; that is, if given twenty minutes before a meal it inhibits much of the normal gastric secretion and so rests the stomach. Dose.—15 to 30 mils (½ to 1 fluid ounce).

Mistura Rhei et Sodae, U.S.P.—MIXTURE OF RHUBARB AND SODA.

Sodium bicarbonate, 3.5; fluidextract of rhubarb, 1.5; fluidextract of ipecacuanha, 0.3; glycerin, 35; spirit of peppermint, 3.5; water, sufficient to produce 100. Average dose.—4 mils (1 fluid drachm).

Pilula Rhei Composita, B.P.—COMPOUND RHUBARB PILL.

Rhubarb root, in powder, 6; Socotrine aloes, in powder, 4.5; myrrh, in powder, 3; hard soap, in powder, 3; oil of peppermint, 0.375; syrup of glucose, 5.5 (or a sufficient quantity). Dose.—2 ½ to 5 decigrams (4 to 8 grains).

Pilula Rhei Composita, P.L., 1851.—COMPOUND RHUBARB PILL, P.L., 1851.

Rhubarb, in powder, 16; Socotrine aloes, in powder, 12; myrrh, in powder, 8; soft soap, 2; oil of caraway, 1; treacle, sufficient to form a mass.

Pilulae Rhei Compositae, U.S.P.—COMPOUND PILLS OF RHUBARB.

Rhubarb in No. 60 powder, 13 grammes; purified aloes, in fine powder, 10 grammes; myrrh, in fine powder, 6 grammes; oil of peppermint, 5 decimils (0.5 milliliters); water, a sufficient quantity. To make 100 pills. Average dose.—2 pills.

Pilulae Rhei et Colocynthidis et Hydrargyri, B.P.C.—RHUBARB, COLOCYNTH, AND MERCURY PILLS.

Each pill contains compound rhubarb pill, 1 grain; compound colocynth pill, 1 grain; mercury pill, ½ grain. Dose.—1 or 2 pills.

Pilulae Rhei et Nucis Vomicae, B.P.C.—RHUBARB AND NUX VOMICA PILLS.

Each pill contains 2 ½ grains of compound rhubarb pill, ¼ grain of extract of nux vomica, ⅛ grain of alcoholic extract of belladonna. Dose.—1 pill.

Pulvis Rhei Compositus, B.P.—COMPOUND POWDER OF RHUBARB. Syn.—Compound Rhubarb Powder; Gregory's Mixture or Powder.

Rhubarb root, in powder, 2; light magnesia, 6; ginger, in powder, 1. Mix the powders lightly, and pass the mixture through a fine sieve, or muslin. This powder is a valuable antacid and laxative for children and delicate persons. Heavy magnesia may be employed in preparing it if a less bulky powder be desired. Dose.—1 to 4 grammes (20 to 60 grains).

Pulvis Rhei Compositus, U.S.P.—COMPOUND POWDER OF RHUBARB, U.S.P.

Rhubarb, in No 60 powder, 25; magnesium oxide, 65; ginger, in No. 60 powder, 10. Average dose.—2 grammes (30 grains).

Pulvis Rhei cum Calomelane, B.P.C.—RHUBARB POWDER WITH CALOMEL.

Rhubarb root, 4; mercurous chloride, 1; ginger, 1. Dose.—2 decigrams (3 grains) for a child twelve months old.

Pulvis Rhei cum Hydrargyro et Soda, B.P.C.—RHUBARB POWDER WITH MERCURY AND SODA. Syn.—Baird's Aperient Powder.

Rhubarb root, 3; mercury with chalk, 1; sodium bicarbonate, 2. Dose.—4 to 8 decigrams (6 to 12 grains).

Pulvis Rhei cum Magnesia, B.P.C.—RHUBARB POWDER WITH MAGNESIA. Syn.—Improved Gregory's Powder.

Rhubarb root, 2; light magnesium carbonate, 6; ginger, 1. Heavy magnesium carbonate may be employed if a less bulky powder be desired. Dose.—1 to 4 grammes (15 to 60 grains).

Pulvis Rhei cum Soda, B.P.C.—RHUBARB POWDER WITH SODA.

Rhubarb root, 1; sodium bicarbonate, 2. This powder may be supplied as a lightly compressed tablet, to be crushed to powder before administration. Dose.—2 decigrams (3 grains) for a child twelve months old.

Syrupus Rhei, B.P.—SYRUP OF RHUBARB.

Rhubarb root, in No. 20 powder, 5; coriander fruit, in No. 20 powder, 5; refined sugar, 60; alcohol, 20; distilled water, 60. Mix the powdered rhubarb root and coriander fruit, moisten the mixture with part of the alcohol and water previously mixed, pack in a percolator after allowing it to stand, and percolate slowly with the remainder of the diluted alcohol; concentrate the percolate by evaporation until the volume is reduced to 35, filter, and dissolve the sugar it, the filtrate by the aid of heat. The weight of the finished product should be about 100. Syrup of rhubarb is used as a purgative for children. Dose.—2 to 8 mils (½ to 2 fluid drachms).

Syrupus Rhei U.S.P.—SYRUP OF RHUBARB, U.S.P.

Fluidextract of rhubarb, 10; spirit of cinnamon, 0.4; potassium carbonate, 1; water, 5; syrup, to 100. Average dose.—8 mils (2 fluid drachms).

Syrupus Rhei Aromaticus, U.S.P.—AROMATIC SYRUP OF RHUBARB.

Aromatic tincture of rhubarb, 15; potassium carbonate, 0.1; syrup, 85. Average dose.—8 mils (2 fluid drachms).

Tablettae Rhei Compositae, B.P.C.—COMPOUND RHUBARB TABLETS.

Each tablet is approximately equal to 3 decigrams (5 grains) of the corresponding official pill mass. Dose.—1 or 2 tablets.

Tablettae Rhei et Sodae, B.P.C.—RHUBARB AND SODA TABLETS.

Each tablet contains rhubarb root, 3 grains, sodium bicarbonate, 1 ½ grains; ginger, 1 grain. Dose.—1 or 2 tablets.

Tinctura Rhei B.P., 1885.—TINCTURE OF RHUBARB.

Rhubarb root, in No. 20 powder, 10; cardamom seeds, bruised, 1.25; coriander fruit, bruised, 1.25; saffron, 1.25; proof spirit, to 100. Dose.—As a stomachic, 4 to 8 mils (1 to 2 fluid drachms); as a purgative, 15 to 30 mils (4 to 8 fluid drachms).

Tinctura Rhei U.S.P.—TINCTURE OF RHUBARB, U.S.P.

Rhubarb root, 20; cardamom fruit, 4; glycerin, 10; alcohol (53 per cent.), sufficient to produce 100. Average dose.—4 mils (1 fluid drachm).

Tinctura Rhei Aquosa, B.P.C.—AQUEOUS TINCTURE OF RHUBARB.

Rhubarb root, in thin slices, 10; borax, 1; potassium carbonate, 1; cinnamon water, 12.5; alcohol, 11.25; distilled water, boiling, 90. This preparation is used as a purgative and stomachic. Dose.—4 to 8 mils (1 to 2 fluid drachms).

Tinctura Rhei Aromatica, U.S.P.—AROMATIC TINCTURE OF RHUBARB.

Rhubarb root, 20; Saigon cinnamon, 4; cloves, 4; nutmeg, 2; glycerin, 10; alcohol (53 per cent.), to 100. Average dose.—2 mils (30 minims).

Tinctura Rhei Composita, B.P.—COMPOUND TINCTURE OF RHUBARB. Syn.—Tinctura Rhei; Tincture of Rhubarb.

Rhubarb root, in No. 20 powder, 10; cardamom seeds, bruised, 1.25; coriander fruit, bruised, 1.25; glycerin, 10; alcohol (60 per cent.), a sufficient quantity. Add 10 of the alcohol to the drugs to moisten the mixture, and proceed with the percolation process until the percolate measures 90; then shake well, allow to stand for forty-eight hours, filter, and mix the filtrate with the glycerin. Compound tincture of rhubarb is given as a purgative in dyspepsia associated with constipation, and in diarrhoea due to intestinal irritation. It is commonly given with antacids. Dose.—2 to 4 mils (½ to 1 fluid drachm), for repeated administration; for a single administration, 8 to 15 mils (2 to 4 fluid drachms).

Vinum Rhei, B.P. 1885.—RHUBARB WINE.

Rhubarb root, in coarse powder, 7.5; canella bark, in coarse powder, 0.685; sherry, to 100. Macerate for seven days, and complete the maceration process Rhubarb Wine is used in dyspepsia associated with constipation. Dose.—1 to 8 mils (1 to 2 fluid drachms).

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.