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Glidant
A glidant is a substance that is added to a powder to improve its flowability. A glidant will only work at a certain range of concentrations. Above a certain concentration, the glidant will in fact function to inhibit flowability. In tablet manufacture, glidants are usually added just prior to compression. Examples Examples of glidants include ascorbyl palmitate, calcium palmitate, magnesium stearate, fumed silica (colloidal silicon dioxide), starch and talc. Mechanism of action A glidant's effect is due to the counter-action of factors that cause poor flowability of powders. For instance, correcting surface irregularity, reducing interparticular friction and decreasing surface charge. The result is a decrease in the angle of repose The angle of repose, or critical angle of repose, of a granular material is the steepest angle of descent or Strike and dip, dip relative to the horizontal plane on which the material can be piled without slumping. At this angle, the mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowability
Flowability, also known as powder flow is a property that defines an ability of a powdered material to flow, related to Cohesion (chemistry), cohesion. Powder flowability depends on many traits: * the shape and size of the powder particles due to intermolecular force, * porosity * Electrostatics, electrostatic activity * hygroscopy * bulk density * angle of repose * presence of glidants * oxidation rate (of a metallic powder) * humidity International Organization for Standardization, ISO 4490:2018 norm (and its precedent, ISO 4490:2014) standardizes a method for determining the flow rate of metallic powders. It uses a normalized/calibrated funnel, named Hall flowmeter. See also * Fluid mechanics * Soil mechanics * Cohesion (geology) * angle of repose References {{Reflist Condensed matter physics Intermolecular forces Physical phenomena Mechanics Geotechnical engineering Fluid mechanics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tablet (pharmacy)
A tablet (also known as a pill) is a pharmaceutical oral dosage form (''oral solid dosage'', or OSD) or solid unit dosage form. Tablets may be defined as the solid unit dosage form of medication with suitable excipients. It comprises a mixture of active substances and excipients, usually in powder form, that are pressed or compacted into a solid dose. The main advantages of tablets are that they ensure a consistent dose of medicine that is easy to consume. Tablets are prepared either by moulding or by compression. The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tabletting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive or aid in visual identification of an unknown tablet. A polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talc
Talc, or talcum, is a clay mineral composed of hydrated magnesium silicate, with the chemical formula . Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material. It is a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate, talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak. Talc is translucent to opaque, with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powder
A powder is a dry solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms ''powder'' and ''granular'' are sometimes used to distinguish separate classes of material. In particular, ''powders'' refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. ''Granulars'' refer to the coarser granular materials that do not tend to form clumps except when wet. Types Many manufactured goods come in powder form, such as flour, sugar, ground coffee, powdered milk, copy machine toner, gunpowder, cosmetic powders, and some pharmaceuticals. In nature, dust, fine sand and snow, volcanic ash, and the top layer of the lunar regolith are also examples. Because of their importance to industry, medicine and earth science, powders have been studied in great detail by chemical engineers, mechanical engineer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', '' molar concentration'', '' number concentration'', and '' volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Dilution is reduction of concentration, e.g. by adding solvent to a solution. The verb to concentrate means to increase concentration, the opposite of dilute. Etymology ''Concentration-'', ''concentratio'', action or an act of coming together at a single place, bringing to a common center, was used in post-classical Latin in 1550 or earlier, similar terms attested in Italian (1589), Spanish (1589), English (1606), French (1632). Qualitative description Often in informal, non- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascorbyl Palmitate
Ascorbyl palmitate is an ester formed from ascorbic acid and palmitic acid creating a fat-soluble form of vitamin C. In addition to its use as a source of vitamin C, it is also used as an antioxidant food additive (E number E304). It is approved for use as a food additive in the EU, the U.S., Canada, Australia, and New Zealand.Australia New Zealand Food Standards Code Ascorbyl palmitate is also marketed as "vitamin C ester". It is synthesized by acylation of vitamin C using different acyl donors. See also * Ascorbyl stearate *Vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ... * Mineral ascorbates References External links Bioavailability of Different Forms of Vitamin C (Ascorbic Acid)Information from the Linus Pauling Institute* {{CPID, id=801 Food antioxidants Fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Palmitate
Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossils of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name comes from Latin ''calx'' "lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceuticals for calcium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Stearate
Magnesium stearate is the chemical compound with the formula . It is a soap, consisting of salt containing two equivalents of stearate (the anion of stearic acid) and one magnesium cation (Mg2+). Magnesium stearate is a white, water-insoluble powder. Its applications exploit its softness, insolubility in many solvents, and low toxicity. It is used as a release agent and as a component or lubricant in the production of pharmaceuticals and cosmetics.Angelo Nora, Alfred Szczepanek, Gunther Koenen, "Metallic Soaps" in Ullmann's Encyclopedia of Industrial Chemistry 2005 Wiley-VCH, Weinheim. Manufacturing Magnesium stearate is produced by the reaction of sodium stearate with magnesium salts or by treating magnesium oxide with stearic acid. Uses Magnesium stearate is often used in food preparations as a anti-adherent and anticaking agent. in the manufacture of medical tablets, capsules and powders. In this regard, the substance is also useful because it has lubricating properties, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumed Silica
Fumed silica (CAS_Registry_Number, CAS number 7631-86-9, also 112945-52-5), also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles. The resulting powder has an extremely low bulk density and high surface area. Its three-dimensional structure results in viscosity-increasing, thixotropic behavior when used as a thickener or reinforcing filler. Properties Fumed silica has a very strong thickening effect. Primary particle size is 5–50 nm. The particles are non-porous and have a surface area of 50–600 m2/g. The density is 160–190 kg/m3. Production Fumed silica is made from flame pyrolysis of silicon tetrachloride or from quartz, quartz sand vaporized in a 3000 °C electric arc. Major global producers are Evonik (who sells it under the name Aerosil), Cabot Corporation (Cab- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, and is contained in large amounts in staple foods such as wheat, potatoes, maize (corn), rice, and cassava (manioc). Pure starch is a white, tasteless and odorless powder that is insoluble in cold water or Alcohol (chemistry), alcohol. It consists of two types of molecules: the linear and helix, helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight. Glycogen, the energy reserve of animals, is a more highly branched version of amylopectin. In industry, starch is often converted into sugars, for example by malting. These sugars may be fermentation, fermented to produce ethanol in the manufacture of beer, whisky and biofuel. In addition, sugars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Charge
A surface charge is an electric charge present on a two-dimensional surface. These electric charges are constrained on this 2-D surface, and surface charge density, measured in coulombs per square meter (C•m−2), is used to describe the charge distribution on the surface. The electric potential is Continuous function, continuous across a surface charge and the electric field is Classification of discontinuities, discontinuous, but not infinite; this is unless the surface charge consists of a dipole layer. In comparison, the potential and electric field both diverge at any point charge or linear charge. In physics, at equilibrium, an ideal Electrical conductor, conductor has no charge on its interior; instead, the entirety of the charge of the conductor resides on the surface. However, this only applies to the ideal case of infinite Electrical resistivity and conductivity, electrical conductivity; the majority of the charge of an actual conductor resides within the Skin effect, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Repose
The angle of repose, or critical angle of repose, of a granular material is the steepest angle of descent or Strike and dip, dip relative to the horizontal plane on which the material can be piled without slumping. At this angle, the material on the slope face is on the verge of sliding. The angle of repose can range from 0° to 90°. The morphology of the material affects the angle of repose; smooth, rounded Sand, sand grains cannot be piled as steeply as can rough, Shear strength (soil), interlocking sands. The angle of repose can also be affected by additions of solvents. If a small amount of water is able to bridge the gaps between particles, electrostatic attraction of the water to mineral surfaces increases the angle of repose, and related quantities such as the bearing capacity, soil strength. When bulk granular materials are poured onto a horizontal surface, a cone (geometry), conical pile forms. The internal angle between the surface of the pile and the horizontal sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
