ABSTRACT
Three different natural cyclodextrins are commonly available on the market, and many derivatives are either already marketed or in development, putting at one’s disposal a large range of products with different water solubilities. Cyclodextrins are produced by the enzymatic degradation of starch. The enzyme cycloglycosyl transferase can be isolated from the culture broth of various bacilli. Two types of methylated cyclodextrin are available: the dimethyl and trimethyl derivatives. Hydroxypropyl cyclodextrins, which are a mixture of variously substituted cyclodextrins, are amorphous products and exhibit a very high water solubility. The most important characteristic of cyclodextrins and their derivatives is their ability to include various molecules inside their hydrophobic cavity, leading to an inclusion compound exhibiting new physicochemical and biological properties. Cyclodextrins are potentially very interesting for the formulator in pharmaceutical technology. The supermolecule resulting from the inclusion of a guest active molecule in a cyclodextrin can differ from the free active molecule in its stability, side effects, solubility, and consequently bioavailability.
