Starch hygroscopicity

Com symps [8029-43 ] (glucose symp, starch symp) are concentrated solutions of partially hydrolyzed starch containing dextrose, maltose, and higher molecular weight saccharides. In the United States, com symps are produced from com starch by acid and enzyme processes. Other starch sources such as wheat, rice, potato, and tapioca are used elsewhere depending on avadabiHty. Symps are generally sold in the form of viscous Hquid products and vary in physical properties, eg, viscosity, humectancy, hygroscopicity, sweetness, and fermentabiHty. 

Nitrostarch gives no color with iodine. It is insoluble in water and does not gelatinize to form a paste as starch does when it is boiled with water. It is not notably hygroscopic, but may take Up 1 or 2% of moisture from a damp atmosphere. It is soluble in acetone. The varieties of nitrostarch which are soluble in ether-alcohol contain about the same amounts of nitrogen as the varieties of nitrocellulose which dissolve in that mixed solvent. Nitrostarch does not form a good film or tough colloid as nitrocellulose does. 

Maltodextrin occurs as a white, slightly hygroscopic powder, as granules of similar description, or as a clear to hazy solution in water. It is a purified, concentrated, nutritive mixture of saccharide polymers obtained by the partial hydrolysis of edible starch. Powders or granules are freely soluble or readily dispersible in water. 

Figure 8 also shows an example of moisture uptake for four selected excipients as a function of relative humidity. Depending on the hygroscopicity of the exscipi-ents, the uptake behaviors are quite variable. Excipients such as microcrystalline cellulose (MCC) and starch can pick up significant amounts of water at relatively low relative humidity. Since this water is not present as a hydrate, it is potentially free to interact with a drug. 

Like many other herbal extracts, valerian extract is very hygroscopic. Inclusion into tablets raises stability issues. Coatings reduce moisture absorption but often lead to tablet explosion or visual deterioration (black specs). Tablets formulated with 250 mg valerian extract, spray-dried lactose, and compressible starch were... 

DNAN forms colorless crystals with a melting point of 120 Celsius. It is fairly soluble in hot water, hot ethanol, methanol, and acetone. It is less soluble in cold water, cold ethanol, and insoluble in chloroform, benzene, ether, and petroleum ether. DNAN is somewhat hygroscopic, and moisture slowly decomposes it—should be stored in a desiccator. A small sample bums leaving a residue of carbon when ignited—a small sample can be detonated by the blow of a hammer. DNAN can be used in explosive compositions when alloyed with TNT, or other low melting secondary explosives, gun propellants with nitrocellulose, nitro starch, or nitroglycerine, and rocket propellants when mixed with ammonium perchlorate. DNAN also demonstrates usefulness for priming mixtures with lead azide, lead styphnate, or diazodinitrophenol, and for use in fireworks. ... 

NTA forms hygroscopic crystals or powder, which are soluble in water, acetone, isopropyl alcohol, and ether. It is used in blasting caps and detonators when mixed with RDX, making demolition charges when admixed with nitrocellulose or nitro starch, and in priming mixtures with lead styphnate, lead azide, or diazodinitrophenol. NTA is acidic and readily forms salts... 

Inulin (Alant Starch, Dahlin, Alantin). (C6H10Os)6 H20, mw 990.86. White, hygroscopic powder or horny amorphous lumps mp 178° (decomposes beginning at 160°), d 1.35-1.4 at 20°/4°. SI sol in cold w, sol in hot w si sol in ale. May be obtained from the bulbs of Dahlia variabilis or other plants. On nitration, it gives an explosive compound... 

Glutinous rice starch has the smallest hygroscopic degenerative nature of all popular starches, but for long storage it is preferable to place the product which contains glutinous rice starch in dry condi-... 

---