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Polyvinyl Acetate Phthalate
Polyvinyl acetate phthalate (PVAP) is a commonly used polymer phthalate in the formulation of pharmaceuticals, such as the enteric coating of Tablet (pharmacy), tablets or capsule (pharmacy), capsules. It is a vinyl acetate polymer that is partially hydrolyzed and then esterified with phthalic acid. Its main use in pharmaceutics is with enteric coating, enteric formulations and controlled release formulations. See also * Cellulose acetate phthalate References Vinyl polymers Acetate esters {{polymer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. 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 compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phthalate
Phthalates ( ), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). While phthalates are commonly used as plasticizers, not all plasticizers are phthalates. The two terms are specific, unique, and not used interchangeably. Lower-molecular-weight phthalates are typically replaced in many products in the United States, Canada, and European Union over health concerns. They are being replaced by higher molecular-weight phthalates as well as non-phthalic plasticizers. Phthalates are commonly ingested in small quantities via the diet. One of the most commonly known phthalates is bis(2-ethylhexyl) phthalate (DEHP). In many countries, DEHP is regulated as a toxin, and is banned from use in broad categories of consumer goods, such as cosmetics, children's toys, medical devices, and fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmaceuticals
Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management. Drugs are classified in many ways. One of the key divisions is by level of control, which distinguishes prescription drugs (those that a pharmacist dispenses only on the medical prescription) from over-the-counter drugs (those that consumers can order for themselves). Medicines may be classified by mode of action, route of administration, biological system affected, or therapeutic effects. The World Health Organization keeps a list of essential medicines. Drug discovery and drug development are complex and expensive endeavors undertaken by pharmaceutical companies, academic scientists, and governments. As a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enteric Coating
An enteric coating is a polymer barrier applied to oral medication that prevents its dissolution or disintegration in the gastric environment. This helps by either protecting drugs from the acidity of the stomach, the stomach from the detrimental effects of the drug, or to release the drug after the stomach (usually in the upper tract of the intestine). Some drugs are unstable at the pH of gastric acid and need to be protected from degradation. Enteric coating is also an effective method to obtain drug targeting (such as gastro-resistant drugs). Other drugs such as some anthelmintics may need to reach a high concentration in a specific part of the intestine. Enteric coating may also be used during studies as a research tool to determine drug absorption. Enteric-coated medications pertain to the "delayed action" dosage form category. Tablets, mini-tablets, pellets and granules (usually filled into capsule shells) are the most common enteric-coated dosage forms. Description Most e ... [...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] |
Capsule (pharmacy)
In the manufacture of pharmaceuticals, encapsulation refers to a range of dosage forms—techniques used to enclose medicines—in a relatively stable shell known as a capsule, allowing them to, for example, be taken orally or be used as suppositories. The two main types of capsules are: * Hard-shelled capsules, which contain dry, powdered ingredients or miniature pellets made by ''e.g.'' processes of extrusion or spheronization. These are made in two-halves: a smaller-diameter "body" that is filled and then sealed using a larger-diameter "cap". * Soft-shelled capsules, primarily used for oils and for active ingredients that are dissolved or suspended in oil. Both of these classes of capsules are made from aqueous solutions of gelling agents, such as animal protein (mainly gelatin) or plant polysaccharides or their derivatives (such as carrageenans and modified forms of starch and cellulose). Other ingredients can be added to the gelling agent solution including plasticizers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Acetate
Vinyl acetate is an organic compound with the Chemical formula, formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohol, and other important industrial polymers. Production The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000). The average list price for 2008 was US$1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%). Vinyl acetate is mainly (80%) polymerized, and the resulting polymer is hydrolyzed to give polyvinvyl alcohol. Preparation Vinyl acetate is the acetate ester of vinyl alcohol. Since vinyl alcohol is highly unstable (with respect to acetaldehyde), the prepara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phthalic Acid
In organic chemistry, phthalic acid is an aromatic dicarboxylic acid, with formula and structure . Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale. Phthalic acid is one of three isomers of benzenedicarboxylic acid, the others being isophthalic acid and terephthalic acid. Production Phthalic acid is produced by the catalytic oxidation of naphthalene or ''ortho-''xylene directly to phthalic anhydride and a subsequent hydrolysis of the anhydride. Phthalic acid was first obtained by French chemist Auguste Laurent in 1836 by oxidizing naphthalene tetrachloride. Believing the resulting substance to be a naphthalene derivative, he named it "naphthalic acid". After the Swiss chemist Jean Charles Galissard de Marignac determined its correct formula, Laurent gave it its present name. Manufacturing methods in the nineteenth century included oxidation of naphthalene tetrach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Release
Modified-release dosage is a mechanism that (in contrast to immediate-release dosage) delivers a drug with a delay after its administration (delayed-release dosage) or for a prolonged period of time (extended-release R, XR, XLdosage) or to a specific target in the body (targeted-release dosage).Pharmaceutics: Drug Delivery and Targeting p. 7-13 Sustained-release dosage forms are s designed to release (liberate) a drug at a predetermined rate in order to maintain a constant drug concentrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellulose Acetate Phthalate
Cellulose acetate phthalate (CAP), also known as cellacefate ( INN) and cellulosi acetas phthalas, is a commonly used polymer phthalate in the formulation of pharmaceuticals, such as the enteric coating of tablets or capsules and for controlled release formulations. It is a cellulose polymer where about half of the hydroxyls are esterified with acetyls, a quarter are esterified with one or two carboxyls of a phthalic acid, and the remainder are unchanged. It is a hygroscopic white to off-white free-flowing powder, granules, or flakes. It is tasteless and odorless, though may have a weak odor of acetic acid. Its main use in pharmaceutics is with enteric formulations. It can be used together with other coating agents, e.g. ethyl cellulose. Cellulose acetate phthalate is commonly plasticized with diethyl phthalate, a hydrophobic compound, or triethyl citrate, a hydrophilic compound; other compatible plasticizers are various phthalates, triacetin, dibutyl tartrate, glycerol, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Polymers
Vinyl may refer to: Chemistry * Polyvinyl chloride (PVC), a particular vinyl polymer * Vinyl cation, a type of carbocation * Vinyl group, a broad class of organic molecules in chemistry * Vinyl polymer, a group of polymers derived from vinyl monomers Materials * PVC clothing, a fabric * Vinyl composition tile, a type of floor tiling * Vinyl siding, an exterior building cladding Music * Vinyl record A phonograph record (also known as a gramophone record, especially in British English) or a vinyl record (for later varieties only) is an analog signal, analog sound Recording medium, storage medium in the form of a flat disc with an inscribed, ...s, phonograph records made with polyvinyl chloride * Vinyl Group, an Australian music technology company * ''Vinyl'' (Dramarama album), 1991 * ''Vinyl'' (William Michael Morgan album), 2016 * ''Vinyl'' (EP), by Dramarama * Vinyl Solution, a record label * "Vinyl", a song by Kira Kosarin Film * ''Vinyl'' (1965 film), direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
