Examples of the application of cyclodextrin in formulation of oral drug preparations

Fendiline hydrochloride [N-/1-phenylethyl/-3, 3-diphenylpropylamine. HCl] is a sparingly soluble and hardly absorbable coronary vasodilator. The fendiline base forms complex with -cyclodextrin in a molar ratio of 12. The enhanced solubility and dissolution rate of the complex resulted in a better bioavailability of the drug, which is represented by the elevated blood levels in rats. The -cyclodextrin complex of PGI₂Me /3% active ingredient content/ was prepared. The freeze-dried powder can be stored at 0°C for 1.5 years, while the pure substance only for 4 months. The biological effectiveness of the complex agrees well with that of the active ingredient. After oral administration the cytoprotective effect of the free and complexed drug on indomethacin induced ulcers in rats was similar in their order of magnitude, however the prolonged effect of the complex was detected in this case too.     

Novel stationary phases for high-performance liquid chromatography analysis of cyclodextrin derivatives

Novel stationary phases were prepared for separation of cyclodextrins and cyclodextrin derivatives by bonding substituted aromatic groups (phenyl and naphthyl) to the silica gel matrix. Both the electron-withdrawing (nitro) and the hydrogen-donor/acceptor (amide or carbamide) substituents of the phenyl group play essential role in the separation of cyclodextrins and cyclodextrin derivatives. On the basis of the comparison of experimental data obtained on different columns the N-(4-nitrophenyl)-carbamide group bonded silica gel stationary phase was selected as the most effective one for analysis of cyclodextrin derivatives. Improved separation potency was observed for hydroxypropylated, methylated and several other cyclodextrin derivatives compared with the previously and presently used stationary phases. Owing to the strong retention of cyclodextrins and its derivatives on the selected column, detection of their decomposition products was easily achieved. Determination of unsubstituted, natural cyclodextrin as an impurity in the cyclodextrin derivatives was implemented. Identification and characterization of cyclodextrin derivatives in industrial products could also be performed.     

Fatty acid-cyclodextrin complexes: Properties and applications

The complexation of fatty acids (both saturated and unsaturated) with various cyclodextrins and cyclodextrin derivatives greatly modifies their properties. Inclusion complex formation — depending upon the type of host cyclodextrin — may result in protection against the environment, in improved water solubility and bioavailability. Thus lipid complexation enables the preparation of more reliable diagnostic reagents, better chromatographic separations and higher yields in biotechnological processes. The relevant literature is reviewed with particular emphasis on the practical utility of the molecular encapsulation of fatty acids with cyclodextrins.     

Extraction of pahs and pesticides from contaminated soils with aqueous cd solutions

A new method for the mobilization of organic pollutants from contaminated soils has been developed using aqueous CD solutions. The CD derivatives (methyl, hydroxypropyl, polymer) are able to desorb the lypophylic xenobiotics (pyrene, pentachlorophenol) sorbed on the particles of the soil and to solubilize these organics via inclusion complex formation and make them more accessible for the microorganisms. The CDs themselves do not pollute the environment being biodegradable.