The encapsulation of hydrophobic drugs in Pluronic F127 micelles: the effects of drug hydrophobicity, solution temperature and pH

摘要

Three drugs, Ibuprofen, Aspirin and Erythromycin, are encapsulated inspherical Pluronic F127 micelles. The shapes and the size distributions of themicelles in dilute, aqueous solutions, with and without drugs, are ascertainedusing cryo- Scanning Electron Microscopy and Dynamic Light Scattering (DLS)experiments, respectively. Uptake of drugs above a threshold concentration isseen to reduce the critical micellization temperature of the solution. The meanhydrodynamic radii and polydispersities of the micelles are found to increasewith decrease in temperature and in the presence of drug molecules. Thehydration of the micellar core at lower temperatures is verified usingfluorescence measurements. Increasing solution pH leads to the ionization ofthe drugs incorporated in the micellar cores. This causes rupture of themicelles and release of the drugs into the solution at the highest solution pHvalue of 11.36 investigated here and is studied using DLS and fluorescencespectrocopy.