Magneto‐sensitive and enzymatic hydrolysis‐resistant systems for the targeted delivery of paclitaxel based on polylactide micelles with an external polyethylene oxide corona

Abstract

AbstractPoly(d,l‐lactide)‐b‐(ethylene glycol) micelles with a mean diameter of 20 nm and a narrow size distribution were obtained by film rehydration. The incorporation of a hydrophobic drug, paclitaxel, into the micelles was studied via various physicochemical methods – dynamic and static light scattering, transmission electron microscopy and infrared spectroscopy. The loading of the hydrophobic drug did not change the morphology of the micelles. By means of MTT tests it was found that, encapsulated in the micelles, paclitaxel retained its activity towards MCF7 cancer cells with cytotoxicity equal to that of commercial drug Taxol®. Modification of the micelles with maghemite nanoparticles resulted in the formation of magneto‐sensitive micelles with fast response to an external magnetic field: saturation magnetization, 0.6 emu g−1; residual magnetization, 0.1 emu g−1; coercive force, 67.5 Oe. The obtained micelles demonstrated high colloidal stability in a wide range of pH during a long period. A study of the behavior of the empty micelles and micelles loaded with paclitaxel and maghemite in the presence of a specific enzyme – proteinase K – showed that micelles underwent hydrolysis only after a long induction period. The obtained results indicate that maghemite‐modified poly(d,l‐lactide)‐b‐(ethylene oxide) micelles are promising for controlled delivery of hydrophobic drugs. © 2021 Society of Industrial Chemistry.