Description
Cyclodextrins refer to a family of compounds consisting of sugar molecules bound together in ring (cyclic oligosaccharides). It is produced from starch through enzymatic conversion. Beta-cyclodextrin is the 7-membered sugar ring molecular form of cyclodextrin. Cyclodextrin has various applications. In the pharmaceutical industry, it can be used as complexing agents for increasing the solubility of poorly soluble drug as well as increasing their bioavailability and stability. It can also alleviate the gastrointestinal drug irritation, and prevent drug-drug and drug-excipient interactions. It can also be used in food, pharmaceutical, drug delivery, and chemical industries, as well as agriculture and environmental engineering.
References
https://en.wikipedia.org/wiki/Cyclodextrin
https://notendur.hi.is/thorstlo/general.pdf
Chemical Properties
beta Cyclodextrin is a virtually odorless, slightly sweet-tasting, white or almost white crystalline solid or fine powder.
Chemical Properties
A biennial herbaceous plant very common in Europe, Asia, Africa and the United States, it has a tapering fleshy
root, furrowed stem, finely cut feathery leaves, umbels of small flower heads in midsummer, and capsules containing two
curved narrow seeds. The plant grows to about 60 cm and it blooms from May to July. The part used is the fruit, containing
approximately 15% of fixed oils and 3 to 7% of essential oil. Caraway has a warm, biting flavor with a strong, fatty, harsh
undernote.
Chemical Properties
Cyclodextrins occur as white, practically odorless, fine crystalline
powders, having a slightly sweet taste. Some cyclodextrin
derivatives occur as amorphous powders.
Chemical Properties
white powder
Occurrence
A derivative of naturally occurring starch.
Uses
Use to solubilize non-polar compounds such as fatty acids, lipids and cholesterol. Reported useful for the selective precipitation of enantiomeric, positional or structural isomersβ-Cyclodextrin is used with dansyl chloride to form water-soluble complexes for fluorescent labeling of proteins. It is an active ingredient of household odor eliminator. It is also used in personal care products like toothpastes, skin creams and dusting powders. It finds applications in the cosmetic industry for products like detergents and perfumes for the controlled release of fragrances. Further, it is used to produce HPLC columns allowing chiral enantiomers separation. In addition to this, it is used to decrease the level of cholesterol in milk fat.
Uses
β-Cyclodextrin is a cyclic oligosaccharide produced from starch via enzymatic conversion. β-Cyclodextrin is commonly used to produce HPLC columns allowing chiral enantiomers separation.
Preparation
Usually produced commercially from Bacillus macerans or B. circulans fermentation of starch or starch hydrolysate.
Production Methods
Cyclodextrins are manufactured by the enzymatic degradation of
starch using specialized bacteria. For example, β-cyclodextrin is
produced by the action of the enzyme cyclodextrin glucosyltransferase
upon starch or a starch hydrolysate. An organic solvent is
used to direct the reaction that produces β-cyclodextrin, and to
prevent the growth of microorganisms during the enzymatic
reaction. The insoluble complex of β-cyclodextrin and organic
solvent is separated from the noncyclic starch, and the organic
solvent is removed in vacuo so that less than 1 ppm of solvent
remains in the β-cyclodextrin. The β-cyclodextrin is then carbon
treated and crystallized from water, dried, and collected.
Definition
ChEBI: Beta-cyclodextrin is a cyclodextrin composed of seven alpha-(1->4) linked D-glucopyranose units.
Essential oil composition
In addition to carvone, the oil contains d-limonene, carveol, diacetyl furfural, methyl alcohol, acetic
aldehyde and other substances. Caraway oil consists of 3.5 to 7% volatile and fatty oils; resin, sugar, tannin, mucilage.
Taste threshold values
Reported to have a taste threshold value lower than that of sucrose with a detection level of 3.9 to 27 ppm
and a recognition level of 11 to 52 ppm
General Description
Beta-Cyclodextrin is the most abundant and cheap cyclic oligosaccharide that forms inclusion complexes with several drug molecules. Its main application is in tablet and capsule formulations.
Pharmaceutical secondary standards for application in quality control, provide pharma laboratories and manufacturers with a convenient and cost-effective alternative to the preparation of in-house working standards.
Flammability and Explosibility
Non flammable
Pharmaceutical Applications
Cyclodextrins are ‘bucketlike’ or ‘conelike’ toroid molecules, with a rigid structure and a central cavity, the size of which varies according to the cyclodextrin type. The internal surface of the cavity is hydrophobic and the outside of the torus is hydrophilic; this is due to the arrangement of hydroxyl groups within the molecule. This arrangement permits the cyclodextrin to accommodate a guest molecule within the cavity, forming an inclusion complex.
Cyclodextrins may be used to form inclusion complexes with a variety of drug molecules, resulting primarily in improvements to dissolution and bioavailability owing to enhanced solubility and improved chemical and physical stability.
Cyclodextrin inclusion complexes have also been used to mask the unpleasant taste of active materials and to convert a liquid substance into a solid material.
b-Cyclodextrin is the most commonly used cyclodextrin, although it is the least soluble. It is the least expensive cyclodextrin; is commercially available from a number of sources; and is able to form inclusion complexes with a number of molecules of pharmaceutical interest. However, b-cyclodextrin is nephrotoxic and should not be used in parenteral formulations. b-Cyclodextrin is primarily used in tablet and capsule formulations.
In oral tablet formulations, b-cyclodextrin may be used in both wet-granulation and direct-compression processes. The physical properties of b-cyclodextrin vary depending on the manufacturer. However, b-cyclodextrin tends to possess poor flow properties and requiresalubricant,such as 0.1% w/w magnesium stearate,when it is directly compressed.
In parenteral formulations, cyclodextrins have been used to produce stable and soluble preparations of drugs that would otherwise have been formulated using a nonaqueous solvent.
In eye drop formulations, cyclodextrins form water-soluble complexes with lipophilic drugs such as corticosteroids. They have been shown to increase the water solubility of the drug; to enhance drug absorption into the eye; to improve aqueous stability; and to reduce local irritation.
Cyclodextrins have also been used in the formulation of solutions,suppositories, and cosmetics.
Biochem/physiol Actions
β-Cyclodextrin is the cyclic α heptamer of glucose. It acts as a host to form inclusion compounds with the guests including derivatives of benzene, cyclohexane, adamantane, other alicyclic guests, and also inorganic molecules or ions. It is generally used to solubilize non-polar compounds such a fatty acids, lipids and cholesterol.
Safety
Cyclodextrins are starch derivatives and are mainly used in oral and
parenteral pharmaceutical formulations. They are also used in
topical and ophthalmic formulations.
Cyclodextrins are also used in cosmetics and food products, and
are generally regarded as essentially nontoxic and nonirritant
materials. However, when administered parenterally, β-cyclodextrin
is not metabolized but accumulates in the kidneys as insoluble
cholesterol complexes, resulting in severe nephrotoxicity.
Cyclodextrin administered orally is metabolized by microflora in
the colon, forming the metabolites maltodextrin, maltose, and
glucose; these are themselves further metabolized before being
finally excreted as carbon dioxide and water. Although a study
published in 1957 suggested that orally administered cyclodextrins
were highly toxic, more recent animal toxicity studies in rats and
dogs have shown this not to be the case, and cyclodextrins are now
approved for use in food products and orally administered
pharmaceuticals in a number of countries.
Cyclodextrins are not irritant to the skin and eyes, or upon
inhalation. There is also no evidence to suggest that cyclodextrins
are mutagenic or teratogenic.
β-Cyclodextrin
LD50 (mouse, IP): 0.33 g/kg(16)
LD50 (mouse, SC): 0.41 g/kg
LD50 (rat, IP): 0.36 g/kg
LD50 (rat, IV): 1.0 g/kg
LD50 (rat, oral): 18.8 g/kg
LD50 (rat, SC): 3.7 g/kg
storage
Cyclodextrins should be stored in a tightly sealed container, in a
cool, dry place.Cyclodextrins are stable in the solid state if
protected from high humidity.
Purification Methods
Recrystallise β-cyclodextrin from water and dry it for 12hours in a vacuum at 110o, or 24hours in a vacuum at 70o. The purity is assessed by TLC on cellulose containing a fluorescent indicator. [Taguchi, J Am Chem Soc 108 2705 1986, Tabushi et al. J Am Chem Soc 108 4514 1986, Orstam & Ross J Phys Chem 91 2739 1987.] [Beilstein 19 IV 6287, 19/12 V 801.]
Regulatory Status
Included in the FDA Inactive Ingredients Database: α-cyclodextrin
(injection preparations); β-cyclodextrin (oral tablets, topical gels);
γ-cyclodextrin (IV injections).
Included in the Canadian List of Acceptable Non-medicinal
Ingredients (stabilizing agent; solubilizing agent ); and in oral and
rectal pharmaceutical formulations licensed in Europe, Japan, and
the USA.
