Spectroscopic investigations of the molecular interaction of anticancer drug mitoxantrone with non-ionic surfactant micelles.

Objectives: The aim of this study was to investigate the interaction of the anticancer drug mitoxantrone with non-ionic micelles, as simple model systems of biological membranes.

Methods: UV-VIS absorption spectroscopy was used to quantify the drug-surfactant micelle interactions in terms of the binding constant and the micelle-water partition coefficient of the drug.

Key Findings: Interaction of mitoxantrone with non-ionic micelles reduces the dimerization process of mitoxantrone, the drug molecules being encapsulated into micelles as monomer.

Evidence for OH radical production during electrocatalysis of oxygen reduction on Pt surfaces: consequences and application.

Multielectronic O(2) reduction reactions (ORR) at Pt surface (and at Au surface for comparison purpose) were examined both in water and in organic solvents using a strategy based on radical footprinting and scanning electrochemical microscopy (SECM). Experiments reveal a considerable and undocumented production of OH radicals when O(2) is reduced at a Pt electrode. These observations imply that the generally admitted description of ORR as simple competitive pathways between 2-electron (O(2) to H(2)O(2)) and 4-electron (O(2) to H(2)O) reductions is often inadequate and demonstrate the occurrence of another 3-electron pathway (O(2) to OH radical).

Scanning electrochemical microscopy studies of glutathione-modified surfaces. An erasable and sensitive-to-reactive oxygen species surface.

A surface sensitive to reactive oxygen species (ROS) was prepared by reduction of a diazonium salt on glassy carbon electrode followed by the chemical coupling of glutathione (GSH) playing the role of an antioxidant species. The presence of active GSH was characterized through spectroscopic studies and electrochemical analysis after labeling of the -SH group with ferrocene moieties. The specific reactivity of GSH vs ROS was evaluated with scanning electrochemical microscopy (SECM) using the reduction of O(2) to superoxide, O(2)(•-), near the GSH-modified surface.

Spectral studies on the molecular interaction of anticancer drug mitoxantrone with CTAB micelles.

The interaction of anticancer drug mitoxantrone with cationic surfactant cetyltrimethylammonium bromide (CTAB) has been investigated by absorption spectroscopy as a function of surfactant concentration ranging from the premicellar to postmicellar region at pH 7.4 and 10. Interaction of mitoxantrone with CTAB micelles induces a bathochromic shift of both absorption maxima and spectral data showed that the micellization reduces the dimerization process and mitoxantrone is bound into micelles in the monomeric form.

Coupled spectral and electrochemical evaluation of the anticancer drug mitoxantrone-sodium dodecyl sulfate interaction.

In-vitro evaluation of the interaction of anticancer drug mitoxantrone with anionic surfactant sodium dodecyl sulfate (SDS), was performed in physiological conditions (phosphate buffer, pH 7.4) by spectral (UV-vis absorption) and electrochemical (cyclic and linear voltammetry) methods. The stoichiometry of interaction, the binding constants and diffusion coefficients of free and bound drug were determined.