Balsamum Tolutanum, B.P. Balsam of Tolu.
Balsam of tolu is obtained from the trunk of Myroxylon Toluifera, H. B. and K. (N.O. Leguminosae), a tree indigenous to New Granada. It is also official in the U.S.P. The balsam exudes from incisions made in the trunk, and is collected in gourds, being afterwards transferred to skins, and finally exported in tins. Balsam of tolu is imported as a soft, tenacious, resinous substance, which becomes harder on keeping, and is quite brittle in cold weather. A small piece warmed and pressed between two pieces of glass forms a transparent yellowish-brown film which exhibits numerous crystals of cinnamic acid when examined under the microscope. The drug has a fragrant odour, and an aromatic, slightly acid taste. Balsam of tolu has sometimes been adulterated with exhausted balsam, and with colophony. The former may be detected by the amount soluble in carbon bisulphide, which should not fall below 25 per cent.; the latter by the non-crystalline nature and saponification number of the residue left on evaporating the solution. The carbon bisulphide residue dissolved in a little glacial acetic acid should not be coloured green by sulphuric acid.
Soluble in alcohol (1 in 1), benzol (1 in 3), chloroform (2 in 1), glacial acetic acid (1 in 1); insoluble in petroleum spirit, and only partially soluble in carbon bisulphide, the portion dissolved in this solvent consisting chiefly of cinnamic acid.
Constituents.—The chief constituents of balsam of tolu are 12 to 15 per cent. of free cinnamic acid, 0.05 per cent. of vanillin, and 7.5 per cent of an oily liquid, consisting of benzyl benzoate mixed with a little benzyl cinnamate. The resin, of which the balsam contains about 80 per cent., yields on saponification an alcohol (tolu-resinotannol) and cinnamic acid, together with a little benzoic acid. Good fresh balsam of tolu yields, when distilled with water, from 1.5 to 3.0 per cent. of a very fragrant volatile oil.
Action and Uses.—The properties of balsam of tolu are similar to those of balsam of Peru, but it is not used externally. Its preparations are used principally for their expectorant action in cases in which the mucus is tenacious and removed with difficulty by coughing.
Dose.—3 to 10 decigrams (5 to 15 grains).
- Liquor Tolutanus, B.P.C.—SOLUTION OF TOLU.
- Balsam of tolu, 10; alcohol, 30; distilled water, 65. Used to prepare a syrup of tolu which is more aromatic than Syrupus Tolutanus, B.P., one volume of the solution being diluted with seven volumes of syrup. The preparation is liable to deposit crystals in cold weather, but they will re-dissolve in the liquid if the bottle containing it be removed to a warm place.
- Syrupus Tolutanus, B.P.—SYRUP OF BALSAM OF TOLU.
- Balsam of tolu, 2.5; refined sugar, 64; distilled water, a sufficient quantity. The resulting syrup should weigh 96. Used in cough mixtures as a flavouring agent and as a mild expectorant. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Syrupus Tolutanus, B.P.C.—SYRUP OF TOLU.
- Solution of tolu, 1; syrup, 7. More aromatic than Syrupus Tolutanus, B.P. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Syrupus Tolutanus, U.S.P.—SYRUP OF TOLU, U.S.P.
- Tincture of tolu (U.S.P.), 5; magnesium carbonate, 1; sugar, 6; triturated together. Add gradually, water, 45; filter and dissolve sugar, 76, in the filtrate with the aid of gentle heat; strain while hot and add water sufficient to produce 100. Average dose.—16 mils (4 fluid drachms).
- Tinctura Tolutana, B.P.—TINCTURE OF BALSAM OF TOLU.
- Balsam of tolu, 10; alcohol, sufficient to produce 100. Used as a disinfectant expectorant in chronic bronchitis. Mixtures containing this tincture require the addition of one-eighth of their bulk of mucilage of gum acacia to suspend the resin in a diffusible form. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Tinctura Tolutana, U.S.P.—TINCTURA OF TOLU.
- Balsam of tolu, 20; alcohol (95 per cent.), sufficient to produce 100. Average dose.—2 mils (30 minims).