Cyclodextrins are crystalline homogenous non-hygroscopic substances which have a cylindrical macro-ring shape, built up from glucopyranose units. A B-cyclodextrin molecule is made up of 7 such units.

Cyclodextrins (CD) can be considered as empty capsules of molecular size (host). When the cavity of CD molecule is filled with a molecule of another substance (guest), such as a meloxicam molecule, it is called an inclusion complex. Only physical forces (no covalent bonding) are involved in the process. The included molecules are oriented in the host in such a position as to achieve the maximum contact between the hydrophobic part of the guest and the non-polar CD cavity. The hydrophilic part of the guest molecule remains at the outer face of the complex. This ensures maximum contact with both the solvent and the hydroxyl groups of the host.

Upon rapid dissociation of the inclusion complex in the stomach, absorption of the guest drug, such as meloxicam, and of the CD are separate processes. While the absorption of the (hydrophobic) guest is strongly accelerated, only an insignificant amount of CD is absorbed. Cyclodextrins are completely resistant to human amylases. They cannot be fermented and cannot be utilized by yeasts. Some hydrolysis takes place in the human colon by the bacterial flora which produce specific cyclodextrinase enzymes. Metabolism of cyclodextrins takes place only in the colon by the microflora. The primary metabolites (maltose, glucose & maltotriose) are then rapidly further metabolized and finally excreted as carbon dioxide and water. Cyclodextrins have no effect on the glucose level of diabetic patients.