Application of hydroxypropyl-β- cyclodextrin in natural medicine

Cyclodextrin (CD)is a truncated cone, The inner cavity of the molecule is hydrophobic, while the outer surface is hydrophilic. most commonly used cyclodextrin is αβ-γ- cyclodextrin by 6, Seven and eight glucose molecules. Currently, β- cyclodextrin is most commonly used, Because it's simple, Low price and internal cavity size are suitable for many guest molecules. But, uh, β- solubility of cyclodextrin and α-γ- in water is low. The reason may be, β- cyclodextrin binds more molecules in crystal state and, β- intramolecular hydrogen bonds on the cyclodextrin ring hinder the formation of hydrogen bonds with the surrounding water molecules and affect the solubility. Therefore, β- cyclodextrin is not suitable for gastrointestinal administration. But β-CD 21 hydroxyl groups can be chemically modified, For improving the physical and chemical properties of natural CD, The most widely used is hydroxypropyl β- cyclodextrin (HP-β-CD).Hydroxypropyl-β- cyclodextrin formed inclusion compounds with volatile oils, flavonoids, alkaloids, phenylpropanoids, quinones, saponins and terpenes, respectively, which masked the bad smell of drugs and increased the solubility of insoluble drugs. Improve the bioavailability of drugs and so on.Basically, it is not catabolized or accumulated in the human body. After oral hydroxypropyl cyclodextrin, the gastrointestinal tract absorbs little, the distribution of blood and urine is very little, most of them are discharged with feces. Non-intestinal administration is also basically excreted with urine.
The hydroxypropyl-β- cyclodextrin is soluble in water, and the solubility is more than 50%(m/V) at room temperature, or even more than 75%(m/V) at room temperature. Therefore, it can not crystallize in alcohol aqueous solution, when its concentration is less than 40%, the fluidity is good and not sticky.hydroxypropyl-β- cyclodextrin can increase the solubility and bioavailability of insoluble drugs. it can be used as a carrier for sustained release, controlled release and targeted preparations. indomethacin eye drops (commercial name Indocid), itraconazole oral and intravenous solutions (commercial name Sporanox), mitomycin intravenous injection (commercial name MitoExtra) and so on.