Saccharum Purificatum, B.P. Refined Sugar.

Related entry: Milk sugar

C₁₂H₂₂O₁₁ = 342.176.
Synonym.—Sucrose.

Refined sugar, or saccharose (Saccharum, U.S.P., Sugar) C₁₂H₂₂O₁₁, is directed in the B.P. to be prepared from the juice of sugar cane, but it is present in the juice of many other plants, notably in that of beetroot, from which much of the sugar of commerce is prepared. It occurs in white, dry, hard, odourless crystals with a pure sweet taste. The aqueous solution is clear, neutral to litmus, and is dextrorotatory. Boiled with dilute acids it is "inverted," and the solution then becomes laevorotatory. An aqueous solution boiled with ammoniacal silver nitrate should not yield more than a slight colouration (absence of glucose). At 160° it fuses, and does not crystallise on cooling; at a higher temperature it becomes black, froths, and tastes bitter. On ignition, it should leave no appreciable residue. For pharmaceutical purposes only the finest quality of cane sugar should be employed, and it should be free from all colouring matter. Burnt sugar or caramel (Saccharum Ustum) may be prepared by heating sugar, with occasional stirring, at about 180° to 200°, until a black, viscid mass is formed, and adding to this while cooling one and a quarter times its weight of hot water. The resulting solution, after straining, is used for colouring purposes; it is precipitated by alcohol. Treacle (Theriaca), the uncrystallised residue from the refining of sugar, is used in the preparation of Chlorodynum, and is sometimes employed as a pill-excipient. It is a thick, very sweet, golden-coloured, fermentable syrup, should be free from empyreumatic odour or flavour, and should not crystallise on keeping. Specific gravity, about 1.40.

Soluble in water (about 1 in 0.45), very soluble in boiling water, alcohol (1 in 100); insoluble in ether, chloroform, or carbon bisulphide.

Action and Uses.—Sugar is an extremely valuable food stuff; it is employed in medicine chiefly as a sweetening agent, and as a demulcent and preservative. Weak solutions of sugar are prone to ferment, but saturated solutions may be preserved indefinitely, the osmotic conditions preventing the growth of low organisms. Sugar prevents the oxidation of substances prone to undergo this change; thus it is a good preservative of ferrous salts in the solid form or in solution. Solutions of sugar dissolve calcium hydrate freely, forming a calcium saccharate as in Liquor Calcis Saccharatus. The syrups are used as flavouring agents and as permanent solutions of active medicinal substances. In large quantities sugar irritates the stomach and bowels and exerts a mild aperient action. For diluting alkaloids and other powerful drugs, milk sugar is preferred, as it is less prone to absorb moisture. Cane sugar may be employed in nutrient enemata, but pure dextrose is usually preferred, as it is more readily absorbed. The use of sugar in large quantities is recommended in such wasting diseases as phthisis and cancer.

PREPARATIONS.

Syrupus, B.P.—SYRUP.

Refined sugar, 66.65; distilled water, sufficient to produce, by weight, 100. Dissolve the sugar in half its weight of the water, by the aid of heat, and add more boiling water if necessary to make the product weigh 100. Specific gravity, 1.33

Syrupus, U.S.P.—SYRUP, U.S.P.

Sugar, 85; distilled water, sufficient to produce, by volume, 100. Specific gravity, about 1.313 at 25°.

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