Introduction Cyclodextrin

Cyclodextrin is a kind of cyclic oligosaccharide. It is composed of multiple glucopyranose molecules to form a cone-shaped cylindrical structure. It has a set of hydrophilic outer rings and a hydrophobic inner cavity ^[2]. The inner cavity contains lipophilic functional groups, thereby improving the solubility, permeability, stability of the molecule, and reducing volatility to reduce odor. ^[1]

Cyclodextrin will increase the aqueous solubility and stability of the drug, without affecting its chemical structure or intrinsic pharmacologic activity. ^[6] In addition, it can also complex toxic substances ^[3] such as phosphobenzene, biphenyl, bisphenol, and other harmful substances, to detoxication of sewage to improve environmental pollution ^[4], so cyclodextrin (Cyclodextrin) is widely used in pharmaceuticals, food, cosmetics, agricultural and environmental engineering, etc.

In addition, the US FDA has approved many products containing cyclodextrin on the market, so the market value of cyclodextrin has excellent growth potential. According to research, the global market will grow to 210 million US dollars until 2024^[8].

Types of cyclodextrin

Cyclodextrin can be divided by the quantity of its glucopyranose monomer three kinds: α-Cyclodextrin (contains 6 glucopyranose monomers), β-Cyclodextrin (contains 7 glucopyranose monomers), and γ-Cyclodextrin (contains 8 glucopyranose monomers), ^[5] the solubility of them is 15%, 1.9%, and 23% (w/v), respectively. Among them, β-Cyclodextrin is the first choice for drug complexing agents, because of its lumen size, high availability, and low cost. ^[6]

Although β-Cyclodextrin has been proved to have excellent performance in pharmaceutical excipients, its low solubility and possible nephrotoxicity make it limited in application. So scientists synthesized β-Cyclodextrin (β-Cyclodextrin) with 1,4-BS(1,4-Butane Sultone) (CAS 1633-83-6) improved it to Sulfobutyl ether beta-cyclodextrin (SEβCD). The reform does not only improve its solubility but also reduces the nephrotoxicity of β-Cyclodextrin, making the application of Sulfobutyl ether β-Cyclodextrin (SEβCD) has huge potential in the drug development market. ^[7]

*Scheme 1. Synthesis reaction for Sulfobutyl ether beta-cyclodextrin (SEβCD)

Further reading: The application of Sulfobutyl ether beta-Cyclodextrin(SEβCD)

Reference:

^[1]Cyclodextrins in pharmaceutical formulations I: structure and physicochemical properties, formation of complexes, and types of complex https://pubmed.ncbi.nlm.nih.gov/26686054/

^[2] Cyclodextrins in pharmaceutical formulations I: structure and physicochemical properties, formation of complexes, and types of complex

^[3] The Cyclodextrins and Their Application in Environmental Biotechnology https://www.sciencedirect.com/science/article/pii/S0166111608703443

^[4] Use of α-cyclodextrin to Promote Clean and Environmentally Friendly Disinfection of Phenolic Substrates via Chlorine Dioxide Treatment https://www.frontiersin.org/articles/10.3389/fchem.2020.00641/full

^[5] Exploring versatile applications of cyclodextrins: an overview https://www.tandfonline.com/doi/pdf/10.3109/10717544.2014.938839

^[6] Cyclodextrins: new drug delivery systems in dermatology https://www.researchgate.net/profile/Thorsteinn-Loftsson/publication/227597926_Cyclodextrins_new_drug_delivery_systems_in_dermatology/links/5e9d5d2992851c2f52b28dcf/Cyclodextrins-new-drug-delivery-systems-in-dermatology.pdf

^[7] Utility of Sulfobutyl Ether beta-Cyclodextrin Inclusion Complexes in Drug Delivery: A Review https://www.ijpsonline.com/articles/utility-of-sulfobutyl-ether-betacyclodextrin-inclusion-complexes-in-drug-delivery-a-review-3659.html

^[8] Global Cyclodextrin Market Growth 2019-2024 https://www.fiormarkets.com/report/global-cyclodextrin-market-growth-2019-2024-373093.html#:~:text=According%20to%20this%20study%2C%20over,US%24%20180%20million%20in%202019