  Three drugs, Ibuprofen, Aspirin and Erythromycin, are encapsulated in
spherical Pluronic F127 micelles. The shapes and the size distributions of the
micelles in dilute, aqueous solutions, with and without drugs, are ascertained
using cryo- Scanning Electron Microscopy and Dynamic Light Scattering (DLS)
experiments, respectively. Uptake of drugs above a threshold concentration is
seen to reduce the critical micellization temperature of the solution. The mean
hydrodynamic radii and polydispersities of the micelles are found to increase
with decrease in temperature and in the presence of drug molecules. The
hydration of the micellar core at lower temperatures is verified using
fluorescence measurements. Increasing solution pH leads to the ionization of
the drugs incorporated in the micellar cores. This causes rupture of the
micelles and release of the drugs into the solution at the highest solution pH
value of 11.36 investigated here and is studied using DLS and fluorescence
spectrocopy.
