β-Cyclodextrin sometimes abbreviated as β-CD, is a hepta
saccharide
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' m ...
derived from
glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
. The α- (alpha), β- (beta), and γ- (gamma)
cyclodextrin
Cyclodextrins are a family of cyclic oligosaccharides, consisting of a macrocycle, macrocyclic ring of glucose subunits joined by α-1,4 glycosidic bonds. Cyclodextrins are produced from starch by enzyme, enzymatic conversion. They are used in ...
s correspond to six, seven, and eight glucose units, respectively. β-Cyclodextrin is the most used natural cyclodextrin in marketed medicines.
The reason for this lies in the ease of its production and subsequent low price (more than 10,000 tons produced annually with an average bulk price of approximately 5 USD per kg).
Structure
In β-cyclodextrin, the seven glucose subunits are linked end to end via α-1,4 linkages. The result has the shape of a tapered cylinder, with seven primary alcohols on one face and fourteen secondary alcohol groups on the other. The exterior surface of cyclodextrins is somewhat hydrophilic whereas the interior core is hydrophobic.
Physical properties
β-Cyclodextrin exists as a white (colorless) powder or crystals. The density of its saturated hydrate crystal (βCD·12H
2O) is 1.46 g/cm
3. β-Cyclodextrin is moderately soluble in water and
glycerin
Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...
; well soluble in
dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is ...
,
dimethylformamide
Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liqui ...
,
pyridine
Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weak ...
,
HFIP, and
ethylene glycol
Ethylene glycol ( IUPAC name: ethane-1,2-diol) is an organic compound (a vicinal diol) with the formula . It is mainly used for two purposes: as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odo ...
; and insoluble in
ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
and
acetone
Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...
.
Applications
β-Cyclodextrin is widely used in medicine, pharmacy, food industry, textiles. Its molecules can accommodate various biomolecules and hence are also used as a complexing agent. Hydrophobic forms of β- CD have been used as sustained release drug carriers. In addition to improving the solubility of compounds, complexation with cyclodextrin has been used to improve the stability of many drugs by inclusion of the compound and protecting certain functional groups from degradation.
Derivatives
β-cyclodextrin has relatively low solubility in water, and hence industry uses its derivatives, such as 2-hydroxypropyl-β-cyclodextrin (HPbCD), randomly methylated β-cyclodextrin (RAMEB), and β-cyclodextrin sulfobutyl ether sodium salt (SBEbCD).
See also
*
α-Cyclodextrin
α-Cyclodextrin (''alpha''-cyclodextrin), sometimes abbreviated as α-CD, is a hexasaccharide derived from glucose. It is related to the β- (beta) and γ- (gamma) cyclodextrins, which contain seven and eight glucose units, respectively. All cycl ...
*
γ-Cyclodextrin
γ-Cyclodextrin sometimes abbreviated as γ-CD, is an octa saccharide derived from glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant ...
References
{{DEFAULTSORT:Cyclodextrin, beta-
Oligosaccharides
Starch
Macrocycles
Chelating agents
E-number additives