On the accessibility of surface-bound drugs on magnetic nanoparticles. Encapsulation of drugs loaded on modified dextran-coated superparamagnetic iron oxide by ß-cyclodextrin.

We report the loading of drugs on aminoethylaminodextran-coated iron oxide nanoparticles, their superparamagnetic behavior, loading of drugs on them, and the ß-cyclodextrin-complex formation of the drugs on the surface of the nanoparticles. The magnetic behavior is studied using vibrating sample magnetometry and X-ray photoelectron spectroscopy is used to analyze the elemental composition of drug-loaded nanoparticles. Scanning electron microscopy shows ordered structures of drug-loaded nanoparticles. UV-visible absorption and fluorescence spectroscopy are used to study the binding of the surface-loaded drugs to ß-cyclodextrin. All of the drugs form 1:1 host-guest complexes. The iodide ion quenching of fluorescence of free- and iron oxide-attached drugs are compared. The binding strengths of the iron oxide surface-loaded drugs-ß-cyclodextrin binding are smaller than those of the free drugs.

Binding of a chromen-4-one Schiff's base with bovine serum albumin: capping with ß-cyclodextrin influences the binding.

This work deals with the synthesis of 6-methyl-3-[(4'-methylphenyl)imino]methyl-4H-chromen-4-one (MMPIMC), its binding to ß-cyclodextrin, and the influence of the cyclodextrin complexation on the compound's binding to bovine serum albumin (BSA). The 1:2 stoichiometry for the complexation of MMPIMC with ß-cyclodextrin is determined with the binding constant of 1.90 × 10(4) M(-2). The structure of host-guest complex plays a role in protein binding of MMPIMC. One- and two-dimensional NMR spectra are used to determine the mode of binding of the guest to ß-cyclodextrin cavity and the structure of the inclusion complex is proposed. The binding of MMPIMC with BSA in the absence and the presence of ß-cyclodextrin is studied. The binding strengths of MMPIMC-BSA (1.73 × 10(5) M(-1)) and ß-cyclodextrin-complexed MMPIMC-BSA (9.0 × 10(4) M(-1)) show difference in magnitude. The Förster Resonance Energy Transfer efficiency and the proximity of the donor and acceptor molecules, are modulated by ß-cyclodextrin. Molecular modeling is used to optimize the sites and mode of binding of MMPIMC with bovine serum albumin.