STOICHIOMETRY AND ASSOCIATION CONSTANTS OF THE INCLUSION COMPLEXES OFELLIPTICINE WITH MODIFIED BETA-CYCLODEXTRIN

Ellipticine is the most representative compound of the small family of pyrido[4,3-b]carbazole alkaloids which exhibit antitumour activity, H owever, its use is plagued by problems associated with its insolubilit y in water and with its detection in clinical analysis, As the use of cyclodextrins (CDs) may alleviate these problems, the inclusion comple xes obtained from ellipticine and gamma-CD as well as a set of complex es with beta-CD or modified beta-CDs were characterized by means of th eir stoichiometry and association constants, The stoichoimetry was 1:1 (ellipticine:CD) for complexes with beta-CD and modified beta-CDs and 1:2 for the ellipticine-gamma-CD complex, Association constants were calculated using spectrofluorimetric data, As they depend on: the pH o f the medium, they mere calculated for different pH values (1.0, 9.1 a nd 13.0), Modified beta-CDs together with gamma-CD gave the highest as sociation constants, The association constants obtained for cationic a nd neutral ellipticine with the different beta-CDs did not differ sign ificantly, These results might lead to an improvement in the chromatog raphic analysis and clinical use of ellipticine.