|
Polyvinylpyrrolidone
Polyvinylpyrrolidone (PVP), also commonly called polyvidone or povidone, is a water-soluble polymer made from the monomer ''N''-vinylpyrrolidone. PVP is available in a range of molecular weights and related viscosities, and can be selected according to the desired application properties. Uses Medical It is used as a binder in many pharmaceutical tablets; it simply passes through the body when taken orally. PVP added to iodine forms a complex called povidone-iodine that possesses disinfectant properties. This complex is used in various products like solutions, ointment, pessaries, liquid soaps and surgical scrubs. It is known under the trade names Pyodine and Betadine, among a plethora of others. It is used in pleurodesis (fusion of the pleura because of incessant pleural effusions). For this purpose, povidone iodine is equally effective and safe as talc, and may be preferred because of easy availability and low cost. PVP is used in some contact lenses and their packagi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excipient
An excipient is a substance formulated alongside the active ingredient of a medication, included for the purpose of long-term stabilization, bulking up solid formulations that contain potent active ingredients in small amounts (thus often referred to as "bulking agents", "fillers", or "diluents"), or to confer a therapeutic enhancement on the active ingredient in the final dosage form, such as facilitating drug absorption, reducing viscosity, or enhancing solubility. Excipients can also be useful in the manufacturing process, to aid in the handling of the active substance concerns such as by facilitating powder flowability or non-stick properties, in addition to aiding ''in vitro'' stability such as prevention of denaturation or aggregation over the expected shelf life. The selection of appropriate excipients also depends upon the route of administration and the dosage form, as well as the active ingredient and other factors. A comprehensive classification system based on struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Povidone-iodine
Povidone-iodine (PVP-I), also known as iodopovidone, is an antiseptic used for skin disinfection before and after surgery. It may be used both to disinfect the hands of healthcare providers and the skin of the person they are caring for. It may also be used for minor wounds. It may be applied to the skin as a liquid or a powder. Side effects include skin irritation and sometimes swelling. If used on large wounds, kidney problems, high blood sodium, and metabolic acidosis may occur. It is not recommended in women who are less than 32 weeks pregnant. Frequent use is not recommended in people with thyroid problems or are taking lithium. Povidone-iodine is a chemical complex of povidone, hydrogen iodide, and elemental iodine. It contains 10% Povidone, with total iodine species equaling 10,000 ppm or 1% total titratable iodine. It works by releasing iodine which results in the death of a range of microorganisms. Povidone-iodine came into commercial use in 1955. It is on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Povidone-iodine
Povidone-iodine (PVP-I), also known as iodopovidone, is an antiseptic used for skin disinfection before and after surgery. It may be used both to disinfect the hands of healthcare providers and the skin of the person they are caring for. It may also be used for minor wounds. It may be applied to the skin as a liquid or a powder. Side effects include skin irritation and sometimes swelling. If used on large wounds, kidney problems, high blood sodium, and metabolic acidosis may occur. It is not recommended in women who are less than 32 weeks pregnant. Frequent use is not recommended in people with thyroid problems or are taking lithium. Povidone-iodine is a chemical complex of povidone, hydrogen iodide, and elemental iodine. It contains 10% Povidone, with total iodine species equaling 10,000 ppm or 1% total titratable iodine. It works by releasing iodine which results in the death of a range of microorganisms. Povidone-iodine came into commercial use in 1955. It is on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyvinylpolypyrrolidone
Polyvinylpolypyrrolidone (polyvinyl polypyrrolidone, PVPP, crospovidone, crospolividone, or E1202) is a highly cross-linked modification of polyvinylpyrrolidone (PVP). The cross-linked form of PVP is used as a disintegrant (see also excipients) in pharmaceutical tablets. PVPP is a highly cross-linked version of PVP, making it insoluble in water, though it still absorbs water and swells very rapidly generating a swelling force. This property makes it useful as a disintegrant in tablets. PVPP can be used as a drug, taken as a tablet or suspension to absorb compounds (so-called endotoxins) that cause diarrhea. (''Cf.'' bone char, charcoal.) It is also used as a fining to extract impurities (via agglomeration followed by filtration). It is used in winemaking. Using the same principle it is used to remove polyphenols in beer production and thus clear beers with stable foam are produced. One such commercial product is called Polyclar. PVPP forms bonds similar to peptidic bonds in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Vinylpyrrolidone
''N''-Vinylpyrrolidone (NVP) is an organic compound consisting of a 5-membered lactam linked to a vinyl group. It is a colorless liquid although commercial samples can appear yellowish. It is produced industrially by vinylation of 2-pyrrolidone, i.e. the base-catalyzed reaction with acetylene. It is the precursor to polyvinylpyrrolidone (PVP), an important synthetic material. The NVP monomer is commonly used as a reactive diluent in ultraviolet and electron- beam curable polymers applied as inks, coatings or adhesives. Synthesis Starting from γ-Butyrolactone, 2-pyrrolidone is synthesized by treatment with ammonia. Subsequently, acetylene is used to introduce the vinyl group In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound contain .... See also * Methylpyrrolidone (NMP) * 2-Pyrro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ointment
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes including creams, foams, gels, lotions, and ointments. Many topical medications are epicutaneous, meaning that they are applied directly to the skin. Topical medications may also be inhalational, such as asthma medications, or applied to the surface of tissues other than the skin, such as eye drops applied to the conjunctiva, or ear drops placed in the ear, or medications applied to the surface of a tooth. The word ''topical'' derives from Greek τοπικός ''topikos'', "of a place". Justification Topical drug delivery is a route of administering drugs via the skin to provide topical therapeutic effects. As skin is one of the largest and most superficial organs in the human body, pharmacists utilise it to deliver various dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solution Polymerization
Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator. The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate. Moreover, the viscosity of the reaction mixture is reduced, preventing autoacceleration at high monomer concentrations. A decrease in viscosity of the reaction mixture by dilution also aids heat transfer, one of the major issues connected with polymer production, since most polymerizations are exothermic reactions. Once the desired conversion is reached, excess solvent must be removed to obtain the pure polymer. Accordingly, solution polymerization is primarily used in applications where the presence of a solvent is desired anyway, as is the case for varnish and adhesives. Another application of polymer solutions includes the manufacture of fibers by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inkjet Printer
Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive consumer models to expensive professional machines. By 2019, laser printers outsold inkjet printers by nearly a 2:1 ratio, 9.6% vs 5.1% of all computer peripherals. The concept of inkjet printing originated in the 20th century, and the technology was first extensively developed in the early 1950s. While working at Canon in Japan, Ichiro Endo suggested the idea for a "Bubble jet" printer, while around the same time Jon Vaught at HP was developing a similar idea. In the late 1970s, inkjet printers that could reproduce digital images generated by computers were developed, mainly by Epson, Hewlett-Packard (HP) and Canon. In the worldwide consumer market, four manufacturers account for the majority of inkjet printer sales: Canon, HP, Eps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inkjet Paper
Inkjet paper is a special fine paper designed for inkjet printers, typically classified by its weight, brightness and smoothness, and sometimes by its opacity. Manufacture Some inkjet papers are made from high quality deinked pulp or chemical pulps. Quality inkjet paper requires good dimensional stability, no curling or cockling, and good surface strength. For most purposes surface smoothness is required. Sufficient and even porosity is required to counteract spreading of the ink. For lower quality printing, uncoated copy paper suffices, but higher grades require coating. The traditional coatings are not widely used for inkjet papers. For matte inkjet papers, it is common to use silica as pigment together with polyvinyl alcohol (PVOH). Glossy inkjet papers can be made by multicoating, resin coating, or cast coating on a lamination paper. A variety of fine art inkjet papers meet the needs of professional photographers and artists. These papers share many characteristics with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical-mechanical Planarization
Chemical mechanical polishing (CMP) or planarization is a process of smoothing surfaces with the combination of chemical and mechanical forces. It can be thought of as a hybrid of chemical etching and free abrasive polishing. Description The process uses an abrasive and corrosive chemical slurry (commonly a colloid) in conjunction with a polishing pad and retaining ring, typically of a greater diameter than the wafer. The pad and wafer are pressed together by a dynamic polishing head and held in place by a plastic retaining ring. The dynamic polishing head is rotated with different axes of rotation (i.e., not concentric). This removes material and tends to even out any irregular topography, making the wafer flat or planar. This may be necessary to set up the wafer for the formation of additional circuit elements. For example, CMP can bring the entire surface within the depth of field of a photolithography system, or selectively remove material based on its position. Typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms ''colloid'' and ''emulsion'' are sometimes used interchangeably, ''emulsion'' should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working. Two liquids can form different types of emulsions. As an example, oil and water can form, first, an oil-in-water emulsion, in which the oil is the dispersed phase, and water is the continuous phase. Second, they can form a water-in-oil emulsion, in which water is the dispersed phase and oil is the continuous phase. Multiple emulsions are als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
