Details

Autor(en) / Beteiligte

• Tóth, Gergő
• Mohácsi, Réka
• Rácz, Ákos
• Rusu, Aura
• Horváth, Péter
• Szente, Lajos
• Béni, Szabolcs
• Noszál, Béla

Titel

Equilibrium and structural characterization of ofloxacin–cyclodextrin complexation

Ist Teil von

• Journal of inclusion phenomena and macrocyclic chemistry, 2013-12, Vol.77 (1-4), p.291-300

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2013

Link zum Volltext

Quelle

Springer journals

Beschreibungen/Notizen

• The enantiomer-specific characterization of ofloxacin–cyclodextrin complexes was carried out by a set of complementary analytical techniques. The apparent stability constants of the ofloxacin enantiomers with 20 different cyclodextrins at two different pH values were determined to achieve good resolution capillary electrophoresis enantioseparation either to establish enantioselective drug analysis assay, or to interpret and design improved host–guest interactions at the molecular level. The cyclodextrins studied differed in the nature of substituents, degree of substitution (DS), charge and purity, allowing a systematic test of these properties on the complexation. The seven-membered beta-cyclodextrin and its derivatives were found to be the most suitable hosts. Highest stability and best enantioseparation were observed for the carboxymethylated-beta-cyclodextrin (DS ~ 3.5). The effect of substitution pattern (SP) was investigated by molecular modeling, verifying that SP greatly affects the complex stability. Induced circular dichroism was observed and found especially significant on carboxymethylated-beta-cyclodextrin. The complex stoichiometry and the geometry of the inclusion complexes were determined by 1 H NMR spectroscopy, including 2D ROESY techniques. Irrespective of the kind of cyclodextrin, the complexation ratio was found to be 1:1. The alfa-cyclodextrin cavity can accommodate the oxazine ring only, whereas the whole tricyclic moiety can enter the beta- and gamma-cyclodextrin cavities. These equilibrium and structural information offer molecular basis for improved drug formulation.