Ethercyclodextrin

Ethercyclodextrin refers to cyclodextrin derivatives in which the hydroxyl groups of the glucose units are converted to ether substituents. Like native cyclodextrins, ethercyclodextrins retain a hydrophobic cavity capable of forming inclusion complexes with certain guest molecules, and their properties can be tuned by the nature and amount of ether substitution.

Synthesis and substitution occur through etherification of cyclodextrin, using alkylating agents such as alkyl halides or epoxides under basic or catalytic conditions. The products are described by the degree of substitution (DS), reflecting the average number of hydroxyl groups replaced per glucose unit. Substituents commonly include methyl, ethyl, or hydroxyalkyl groups, yielding methylated, ethylated, hydroxypropyl, and related ethers. Substitution patterns are typically non uniform, resulting in a mixture of regioisomers and varied DS.

Properties and applications depend on the substituents and DS. Ether modifications often enhance or modify water solubility and binding characteristics relative to native cyclodextrins. Hydroxypropyl- and other hydroxyalkyl ethers are particularly prevalent as pharmaceutical excipients, improving solubility and stability of incorporated drugs and influencing inclusion complex formation. Other ether derivatives are used in solubilization, formulation development, or analytical applications.

Regulatory status and safety are specific to the particular derivative and its substitution level, with some ethercyclodextrins approved as excipients in certain regions and others used primarily in research. Related compounds include other cyclodextrin derivatives such as methylated and hydroxypropyl cyclodextrins.