Controlled Release Characteristics of Aqueous PEO‐PPO‐PEO Micelles With Added Malachite Green, Erythrosin, and Cisplatin Determined by UV–Visible Spectroscopy

Abstract

Dynamic diffusion experiments were performed on aqueous polymeric micelles mixed with malachite green (0.05% mass v−1), erythrosin (0.1% mass v−1), and cisplatin (0.1% mass v−1) to gauge release from sequestered structures using ultraviolet–visible spectroscopy. The additives were formulated with 20% mass v−1 aqueous solutions of polyethylene oxide‐polypropylene oxide‐polyethylene oxide, PEO‐PPO‐PEO (F127). Each additive was tested neat at room temperature, neat at 40 °C, and formulated with F127 at room temperature, and 40 °C. After constructing calibration curves, the dynamic release for each ternary additive and corresponding diffusion coefficients were calculated. Results show that F127 retards permeation at room temperature. In general, the neat additives at 40 °C showed the highest permeability for both malachite green and erythrosin. Malachite green released almost 90% of the dye by 60 min of permeation. When formulated with F127 at 40 °C, sizeable release was still noted, but with an induction period of 10–30 min to register release. The behavior with cisplatin was more complicated as the first 5 h of permeation resulted in a burst delivery with cisplatin (6% total release with cisplatin‐F127‐RT compared to 4% total release cisplatin‐RT) but with overall lower release. The higher fluence at elevated temperature is attributed to reducing the blocking effect of the amphiphiles on the walls of the dialysis tubing as they are directed to form colloidal gels. There is also likely a correlation between higher temperature and higher overall permeability if the membrane pores also expand with temperature.