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- Introduction and General Overview of Cyclodextrin Chemistry
- Introduction and General Overview of Cyclodextrin Chemistry.
Cyclodextrins are produced from starch by enzymatic conversion. They are used in food, pharmaceutical, drug delivery , and chemical industries, as well as agriculture and environmental engineering.
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Cyclodextrins are produced from starch by enzymatic conversion. They are used in food, pharmaceutical, drug delivery , and chemical industries, as well as agriculture and environmental engineering. The largest cyclodextrin contains 32 1,4-anhydroglucopyranoside units, while as a poorly characterized mixture, at least membered cyclic oligosaccharides are also known. Typical cyclodextrins contain a number of glucose monomers ranging from six to eight units in a ring, creating a cone shape:.
With a hydrophobic interior and hydrophilic exterior, cyclodextrins form complexes with hydrophobic compounds. Alpha-, beta-, and gamma-cyclodextrin are all generally recognized as safe by the U. The cyclodextrin confers solubility and stability to these drugs. Cyclodextrins were also shown to enhance mucosal penetration of drugs.
Cyclodextrins bind fragrances. Such devices are capable of releasing fragrances during ironing or when heated by human body. Such a device commonly used is a typical 'dryer sheet'. The heat from a clothes dryer releases the fragrance into the clothing. Cyclodextrins are also used to produce alcohol powder by encapsulating ethanol.
The powder produces an alcoholic beverage when mixed with water. Typical cyclodextrins are constituted by glucopyranoside units. These subunits are linked by 1,4 glycosidic bonds. The cyclodextrins have toroidal shapes, with the larger and the smaller openings of the toroid exposing to the solvent secondary and primary hydroxyl groups respectively.
Because of this arrangement, the interior of the toroids is not hydrophobic , but considerably less hydrophilic than the aqueous environment and thus able to host other hydrophobic molecules.
In contrast, the exterior is sufficiently hydrophilic to impart cyclodextrins or their complexes water solubility. They are not soluble in typical organic solvents. Cyclodextrins are prepared by enzymatic treatment of starch. As an alternative a "complexing agent" can be added during the enzymatic conversion step: such agents usually organic solvents like toluene , acetone or ethanol form a complex with the desired cyclodextrin which subsequently precipitates. The complex formation drives the conversion of starch towards the synthesis of the precipitated cyclodextrin, thus enriching its content in the final mixture of products.
Wacker Chemie AG uses dedicated enzymes, that can produce alpha-, beta- or gamma-cyclodextrin specifically. This is very valuable especially for the food industry, as only alpha- and gamma-cyclodextrin can be consumed without a daily intake limit. Interest in cyclodextrins is enhanced because their host—guest behavior can be manipulated by chemical modification of the hydroxyl groups. O- Methylation and acetylation are typical conversions. Propylene oxide gives hydroxypropylated derivatives.
The degree of derivatization is an adjustable, i. In supramolecular chemistry , cyclodextrins are precursors to mechanically interlocked molecular architectures , such as rotaxanes and catenanes. Beta-cyclodextrin complexes with certain carotenoid food colorants have been shown to intensify color, increase water solubility and improve light stability. Cyclodextrins, as they are known today, were called "cellulosine" when first described by A. Villiers in These compounds were therefore referred to as "Schardinger sugars".
For 25 years, between and , Pringsheim in Germany was the leading researcher in this area, demonstrating that cyclodextrins formed stable aqueous complexes with many other chemicals. By the mids, each of the natural cyclodextrins had been structurally and chemically characterized and many more complexes had been studied.
Since the s, extensive work has been conducted by Szejtli and others exploring encapsulation by cyclodextrins and their derivatives for industrial and pharmacologic applications. Cyclodextrins are of wide interest in part because they are nontoxic. The LD50 oral, rats is on the order of grams per kilogram. From Wikipedia, the free encyclopedia.
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Bakke et al. Cyclodextrin promotes atherosclerosis regression via macrophage reprogramming. Science Translational Medicine: 8 , ra50 doi : Scientific reports, 7 1 , Sci Rep 9, doi : Hidden categories: CS1 maint: uses authors parameter Wikipedia articles needing page number citations from April Namespaces Article Talk. Views Read Edit View history. Help Learn to edit Community portal Recent changes Upload file. Download as PDF Printable version.
Introduction and General Overview of Cyclodextrin Chemistry
It seems that you're in Germany. We have a dedicated site for Germany. Authors: Bender , M. Thus, systems that exhibit "host-guest" relationships, i. The cyclodextrins are the first and probably the most important example of compounds that exhibits complex formation. This is a book about the cyclodextrins. There are of course other compounds that exhibit "host-guest" relationships and thus bind other organic molecules, but so far they have not achieved the importance of the cyclodextrins.
Request PDF | On Sep 29, , J. SZEJTLI published ChemInform Abstract: Introduction and General Overview of Cyclodextrin Chemistry.
Introduction and General Overview of Cyclodextrin Chemistry.
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