Dextrose, anhydrous

Equip a 500 ml. three-necked flask with an efficient stirrer (e.g., a Hershberg stirrer. Fig. II, 7, 8) and a reflux condenser stopper the third neck. Place a solution of 30 g. of sodium hydroxide in 100 ml. of water, and also 20-5 g. (17-1 ml.) of pure nitrobenzene in the flask, immerse it in a water bath maintained at 55-60°, and add 21 g. of anhydrous dextrose in small portions, with continuous stirring, during 1 hour. Then heat on a boiUng water bath for 2 hours. Pour the hot mixture into a 1 litre round-bottomed flask and steam distil (Fig. II, 40, 1) to remove aniline and nitrobenzene. When the distillate is clear (i.e., after about 1 htre has been collected), pour the residue into a beaker cooled in an ice bath. The azoxybenzene soon sohdifies. Filter with suction, grind the lumps of azoxybenzene in a mortar, wash with water, and dry upon filter paper or upon a porous plate. The yield of material, m.p. 35-35-5°, is 13 g. Recrystallise from 7 ml. of rectified spirit or of methyl alcohol the m.p. is raised to 36°. ... 

Anhydrous -dextrose can be crysta11i2ed from concentrated solutions or melts at 90% soHds at a temperature above 100°C. By carefully controlling conditions, a product containing a high percentage of anhydrous -dextrose can be obtained. 

Analysis and Specifications. Typical product analyses include sohds level, ash, color, conductivity, purity, and minor saccharide levels (19). Specifications for anhydrous and monohydrate crystalline dextrose are available (15). High quahty anhydrous dextrose produced for the pharmaceutical industry is prepared in accordance with additional specifications (20). 

The problem of crystallizing dextrose from starch conversion liquor in a form which would allow separation from the viscous mother liquor was attacked in the latter part of the nineteenth century by various workers. The most successful efforts were made by Behr in 1881.3 Corn starch was hydrolyzed at low concentration, the refined product was concentrated, seeded with a very small proportion of pure anhydrous dextrose crystals, and it was then allowed to stand without agitation in heated rooms. Care was taken to exclude any traces of dextrose hydrate crystals. After several days the crystalline magma was separated and washed in centrifugal filters. By this means individual crystals of anhydrous dextrose of suitable size were obtained and the product... 

How many milliosmoles per liter are represented by a solution that contains 50% anhydrous dextrose in water for injection ... 

Molecular weight of anhydrous dextrose =180 50% solution contains 500 g per liter... 

Refining. After saccharification, the hydrolyzate is clarified by precoat filtration, or possibly membrane filtration, to remove traces of insoluble fat, protein, and starch. Treatment with powdered carbon, granular carbon, and/or ion-exchange resins is then used to remove residual trace impurities, color, and inorganic constituents. The refined hydrolyzate can be dried to a solid product, evaporated to a high dextrose syrup, or processed to crystalline monohydrate or anhydrous dextrose. A typical process for production of crystalline dextrose is shown in Figure 2(7). 

Anhydrous dextrose is purified, crystalline D-glucose without water of crystallization. 

Either anhydrous dextrose or dextrose monohydrate can be obtained by crystallization. Monohydrate crystallizers are large horizontal, cylindrical batch tanks or... 

Glucose Standard Solution Dissolve 36.0 mg of anhydrous dextrose in Phosphate Buffer in a 1000-mL volumetric flask, dilute to volume with water, and mix. 

Moisture content anhydrous dextrose absorbs significant amounts of moisture at 25°C and a relative humidity of about 85% to form the monohydrate. The monohydrate similarly only absorbs moisture at around 85% relative humidity and 25°C. See Eigure 1. 

Figure 1 Sorption-desorption isotherm for anhydrous dextrose granules.

Synonyms anhydrous dextrose anhydrous D-(- -)-glucopyra-nose anhydrous glucose dextrosum anhydricum. Appearance white, odorless, crystalline powder with a sweet taste. 

The way in which the strengths of dextrose solutions are expressed varies from country to country. The JP 2001 requires strengths to be expressed in terms of dextrose monohydrate, while the BP 2004 andUSP 28 require strengths to be expressed in terms of anhydrous dextrose. Approximately 1.1 g of dextrose monohydrate is equivalent to 1 g of anhydrous dextrose. 

Armstrong NA, Patel A, Jones TM. The compressional properties of dextrose monohydrate and anhydrous dextrose of varying water contents. In Rubinstein MH, ed. Pharmaceutical Technol-ogy Tableting Technology, vol. 1. Chichester Ellis Horwood, 1987 127-138. 

Armstrong N, Patel A, Jones T. The compression properties of dextrose monohydratc and anhydrous dextrose of varying water ctmtent. Drug Dev Ind Pharm 1986 12 1885-901. Greonwold H. Lerk CF, Mulder RJ. Some aspects of the failure of sucrose tablets. J Pharm Hiarmacol 1972 24 352-6. 

High dextrose equivalent hydrolyzates can be handled so as to crystallize dextrose and remove the impurities as hydrol. In this way dextrose hydrate is produced, having a dextrose equivalent of 99.6+ and 8.5% water of crystallization. This is a white crystalline compound. If suitable conditions are used, crystalline anhydrous dextrose with substantially no water can also be produced. These two types of crystalline sugar are both regular items of commerce. 

While pure dextrose monohydrate has a melting point of 244° to 248° F., the commercial product evidently has some free water since it melts readily in a boiling-water bath (actually at about 180° F.), forming a semistable sirup. Anhydrous dextrose melts at 295° F. In this respect dextrose is different from sucrose, which does not melt, but decomposes at 367° F. This distinction is not generally important in food uses, as water is almost always present and solution occurs. 

Cameron reported that in 10% solution of sucrose as a basis of comparison, dextrose had a relative sweetness of 68.5% and fructose or levulose was 20.5% sweeter than sucrose (1). The most widely accepted sweetness for anhydrous dextrose is 70 to 75% that of sucrose. Calculating resultant sweetness of a 10% sucrose solution converted to invert sugar based on equivalent dextrose sweetness, we get from Cameron s figures ... 

B. Dextrose and related products Dextrose, anhydrous Dextrose, hydrated Glucose... 

Cerekse. [Com Prods.] Dextrose, anhydrous dextrose, liq. dextrose. 

The starting material for the charcoals was Baker and Adamson anhydrous dextrose charred in air at temperatures less than 300°. Samples of this material were heated in air, in nitrogen, in an evacuated sealed tube, and under continuous evacuation by a mercury diffusion pump at various temperatures, in some cases up to 780°. 

Dextrose crystallizes with difficulty from water, in which it is very soluble. The crystals contain one molecule of water, and are in the form of microscopic six-sided plates, which grow in masses they melt at 86°. They are.obtained most readily by crystallizing dextrose from 80 per cent alcohol. Anhydrous dextrose is obtained from 95 per cent methyl or ethyl alcohol. In this form the carbohydrate melts at 146°. Pure dextrose is approximately three-fifths as sweet as sugar. It is optically active. 

Ascorbic acid (+)-calcium pantothenate (-)-carvone anhydrous dextrose ephedrine hydrochloride (+)-litnonene L-lysine mannitol monosodium glutamate norephedrine hydrochloride quinidine sulphate quinine sulphate sorbitol L-threonine L-tryptophan tartaric acid all amino acids most sugars, e.g., glucose, xylose, ribose. 

Glucose Glucose, commercial name dextrose, in the aldohexose form a-o-glucose [CsHizO ), is the major product from starch hydrolyzed by acid and/or enzymes. The major starch source in the USA and Japan is corn Zea mays) and in Europe, wheat and potato. There is some starch and starch hydrolyzate production from cassava in the tropics. Glucose is sold as anhydrous dextrose more commonly as dextrose monohydrate, as glucose syrup or corn syrup. 

---