Cyclodextrins and their Derivatives in Drug Delivery: A Review

The objective of the present review is to discuss the role and applications of cyclodextrins and their derivatives in drug delivery. Cyclodextrins are useful functional excipients that have enjoyed widespread attention and use. They are a family of cyclic oligosaccharides with a hydrophilic outer surface and a lipophilic central cavity. Cyclodextrins have been used in the pharmaceutical industry as complexing agents to increase aqueous solubility of poorly soluble drugs, to increase stability, bioavailability and reduced drug irritation. Applications in the different drug delivery systems like oral, sublingual, buccal, ocular, nasal, transdermal, rectal, pulmonary, parenteral, colon-specific delivery, brain drug delivery, novel delivery systems like liposomes, nanoparticles, microparticles, in gene delivery and oligonucleotide delivery are discussed. Studies in both humans and animals have shown that cyclodextrins can be used to improve drug delivery from almost any type of drug formulation. However, addition of cyclodextrins to existing formulations without further optimization will seldom result in acceptable outcome. A number of cyclodextrin-based products have reached the market based on their ability to camouflage undesirable physicochemical properties.