Gastrointestinal tract cyclodextrins

Cyclodextrins appear to be extremely biocompatible. They are unable to significantly permeate biological membranes and are not absorbed by the gastrointestinal tract yet do not induce a response from the body s immune system. Tests on rats indicate that LD50 values for the most toxic parent compound, /7-cyclodextrin, are greater than 5 g per kg of body weight when administered orally and 0.5 g per kg of body weight when administered intravenously. This low level of toxicity, coupled to the cyclodextrins ability to form inclusion complexes, makes them ideal excipients in pharmaceutical formulations. 

Cyclodextrins (CDs) are cyclic oligomers of or-D-glucose units linked by o - ,4 glycosidic bonds in a donut-shaped ring [1]. CDs are non-toxic ingredients that are not absorbed in the upper gastrointestinal tract and almost metabolized by the colon micro flora [2]. They, therefore, provide health benefits to people. 

It was reported [93] that flurbiprofen-cyclodextrin prodrugs were stable in the pH environment of the gastrointestinal tract and hydrolyzed to release free flurbiprofen by the action of enzymes produced by microflora in rat colon. Furthermore, the prodrug showed a great potential in treatment of colitis induced by acetic acid since it significantly decreased the extent and severity of colonic damage induced by acetic acid. 

---