In acid media MeP becomes oxidized as ferrocene in neutral medium, in a reversible one-electron process, whose rate (at the potential of the current plateau) is limited essentially by the diffusion of micelle particules containing the electroactive compound.
This mesh size reduction led to a decrease in the effective diffusion coefficient of micelles in the gel, and extended the release time of dexamethasone from 2 h in surfactant-free hydrogel to more than 2 days in the micelle-laden hydrogel.
However, the diffusion of the micelles was very influenced by the increment of the solution viscosity caused by the polystyrene chains.
Diffusion of the micelles in solution in the presence of poly methyl methacrylate) (PMMA) or polystyrene homopolymer (h-PS), from dilute to semidilute, has been investigated by laser light scattering (LLS).
The results obtained show that the extraction process is mediated by an instantaneous interfacial reaction, being controlled by the diffusion of the reversed micelles in the organic phase.
A mass transfer model is presented to determine the particle size distribution and dissolution rate in terms of two steps: interfacial reaction, consisting of micelle uptake and desorption, followed by diffusion of the drug-loaded micelles.
The adsorption kinetics was investigated and analyzed by a model considering both the effects of diffusion and micelles reorganization on the PS surface.
In the absence of micelles, the diffusion measurements indicate an oligomeric state of even larger than octadecamer (18 molecules) for SP-A.
In particular, a high amounts of curcumin released were observed in delivery systems containing high Tween 60 concentrations, which was attributed to rapid diffusion of curcumin-loaded surfactant micelles out of the beads.
The autocorrelation functions in Figure 5a were measured independently for the two fluorophores by exciting Atto 488-labeled KcsA S6C) at 488 nm and Rh-PE at 633 nm, revealing that both existed as single populations with identical diffusion times of 3.05 ms. Resolubilization of proteoliposomes gave rise to a single population having a diffusion time of 0.17 ms characteristic of micelles.
