Glucosum. Glucose.; Pure Anhydrous Glucose, Dextrose, Pure Grape Sugar; Glucosum liquidum, Liq
Other tomes: Felter
C6H12O6 = 180.096.
Synonyms.—Pure Anhydrous Glucose; Dextrose; Pure Grape Sugar.
Glucose, C6H12O6, is obtained by the inversion of starch, the process employed being similar to that described under Glucosum Liquidum, but more acid is employed to prevent any dextrin remaining unconverted, and conversion carried a stage further. It occurs as anhydrous hard crusts or in fine powder. It crystallises from water or dilute alcohol with one molecule of water, forming nodular masses (melting-point, 86°), but it loses its water of crystallisation at 110°; anhydrous glucose is deposited from concentrated aqueous solutions at a temperature of 30° to 35°. Alcoholic solutions also deposit anhydrous glucose in microscopic needles, which melt at 140°. A solid glucose is found in commerce in crystalline masses or lumps containing 12 to 14 per cent. of water. It consists of dextrose (about 60 per cent.) with an unfermentable dextrin-like substance termed gallisin, and may be employed in the preparation of nutrient media for use in bacteriology and in the preparation of compressed tablets.
Soluble in water, alcohol, or glycerin.
Action and Uses.—A solution of pure glucose has been recommended for use by subcutaneous injection as a restorative after severe operations, or as a nutritive in wasting diseases, a litre of 5 per cent. solution (which is isotonic with the blood) being injected in the course of twenty-four hours; it has also been used to augment the movements of the uterus. Glucose is added to nutritive enemata for rectal alimentation. Its use has also been recommended for rectal injection and by the mouth in delayed chloroform poisoning.
- Enema Nutriens, B.P.C.—NUTRIENT ENEMA.
- Glucose, 10; solution of pancreatin, 2.5; yolk and white of egg, 20; milk, to 100. Quantity for one application is 60 to 120 mils (2 to 5 fluid ounces).
- Liquor Glucosi et Sodii Chloridi, B.P.C.—GLUCOSE AND SODIUM CHLORIDE SOLUTION. Syn.—Saccharo-saline Solution.
- Pure anhydrous glucose, 2.5; sodium chloride, 0.45; distilled water, to 100. This solution is isotonic with blood serum, and after sterilisation is used as a restorative injection.
Liquid glucose of commerce is a saccharine substance obtained by the hydrolysis of starch. The starch is treated with diluted sulphuric acid, and steam passed through the mixture; or the starch and diluted acid are enclosed in strong copper cylinders and subjected to the action of steam under pressure. When hydrolysis is complete and the mixture ceases to give a reaction with iodine, the acid is neutralised by chalk or marble dust, the solution treated with animal charcoal, filtered, and evaporated in vacuo. If sulphuric acid be used it must be free from arsenic, as the latter would pass into the glucose and consequently into any preparations made from it. Commercial liquid glucose occurs as a clear, viscid, almost colourless and odourless syrup, with a sweet taste. Its solutions usually have a faintly acid reaction. It consists chiefly of dextrose, but dextrin is also present along with variable percentages of unfermentable carbohydrates, among these being the dextrin-like substance, gallisin. Glucose undergoes direct vinous fermentation, reduces Fehling's solution at once when heated, and is decomposed by alkalies, becoming brown and partially changed to mannose and fructose. When warmed with solution of ammonio-nitrate of silver, metallic silver is precipitated; with solution of mercuric cyanide in solution of potassium hydroxide, metallic mercury is thrown down. Traces of calcium sulphate are frequently present in commercial liquid glucose, being derived from the chalk used to neutralise the excess of acid employed in the process of manufacture. Sulphurous acid, in the form of sulphites, is nearly always found in commercial glucose, being used as a preservative or for decolourising. It is frequently present in such quantity as to give a distinctly sulphurous taste.
Soluble in water, alcohol, or glycerin.
Action and Uses.—Liquid glucose is used chiefly as a pill excipient, either alone or diluted with two parts of syrup, as in the B.P. syrup of glucose, or diluted with an equal quantity of syrup. For coloured pills many dispensers prefer a mixture of equal weights of extract of gentian and liquid glucose. Liquid glucose is specially suitable for the preparation of pills containing ferrous carbonate. It preserves the ferrous salt from oxidation, and will even reduce any ferric salt present. Conversely, it should not be used where such reduction is to be avoided, as in the preparation of pills containing cupric salts.
- Syrupus Glucosi, B.P.—SYRUP OF GLUCOSE.
- Liquid glucose, 1; syrup, 2; by weight. Stir together, warming gently until mixed. It is used as a pill excipient, but a mixture of equal parts of liquid glucose and syrup answers the purpose better.