Hidrogeles de ciclodextrinas para administración de fármacos

Abstract

Cyclodextrins (CDs) are cyclic oligosaccharides consisting of six to eight ring glucose units linked by α(1-4) bonds, so as to form a toroid in which the hydrophilic groups are exposed to the outside. This arrangement determines that CDs can form inclusion complexes with a variety of drugs bearing low polar groups. Traditionally, CDs have been used individually dispersed to improve the physicochemical and biopharmaceutical properties of many drugs. This approach has the limitation that the dilution in physiological medium triggers rapid rupture of the complexes, with the risk of drug precipitation. Incorporation of CDs into polymeric networks leads to synergies that greatly increase their performance. CDs enable tuning of network properties and endow it with a new mechanism of drug incorporation and control of release; on the other hand, the confinement of the CDs in a network which, when administered to the body, slowly disintegrates provides a high local concentration of CDs which slows down decomplexation. In this chapter the possibilities of incorporation into polymer networks of free CDs, the formation of poly(pseudo)rotaxanes with chemically bonded CDs, grafting of CDs to the polymer backbone or as pendant structures, are reviewed in the context of pharmaceutical technology and regenerative medicine.