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. The strength of the interaction between mitoxantrone and non‐ionic micelles is higher at pH 10 than at pH 7.4, and depends on the surfactant in the order Tween 80 > Tween 20 > Triton X‐100. The higher partition coefficient at pH 10 compared to pH 7.4 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. Conclusions 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.