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

Abstract

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. 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. Interaction of mitoxantrone with non-ionic micelles reduces the dimerization process of mitoxantrone, the drug molecules being encapsulated into micelles as monomer. The strength of the interaction between mitoxantrone and non-ionic micelles is higher at pH10 than at pH7.4, and depends on the surfactant in the order Tween 80>Tween 20>Triton X-100. The higher partition coefficient at pH10 compared to pH7.4 suggests that at basic pH the deprotonated mitoxantrone is incorporated more efficiently into the hydrophobic medium of non-ionic micelles compared to physiological pH, when the protonated drug is predominant. These results on simple model systems miming the drug-membrane interactions contribute to the elucidation of the behaviour of the drug in vivo, as well as the possible utilization of surfactant micelles as drug carriers.