Adsorption and controlled release of iron-chelating drug from the amino-terminated PAMAM/ordered mesoporous silica hybrid materials

Abstract The present study aimed to assess the adsorption behavior and release kinetics of iron chelating drug, deferasirox, from a series of amino-terminated polyamidoamine dendrimer/ordered mesoporous silica hybrids ( G 1 MCM −41, G 2 MCM -41, and G 3 MCM -41). The synthesized PAMAM-modified MCM-41 materials were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, dynamic light scattering, zeta potential, and elemental analysis. Adsorption isotherms were analyzed using Langmuir, Freundlich, Sips, and Redlich-Peterson models. Sips isotherm was the model that best fitted equilibrium data which revealed a maximum adsorption capacity of 419 mg/g for G 3 MCM -41. The negative values of Gibbs free energy change demonstrated the spontaneous nature of adsorption of deferasirox onto carriers. The release study results showed that the nanoparticles with lower generation had more pH-sensitivity, however, G 3 MCM -41, which released most of the drug in the lowest pH (pH 4.5), seems to be the most suitable generation for efficient delivery of deferasirox. Korsmeyer-Peppas, Weibull and Peppas-Sahlin kinetic models were applied to describe the dissolution profile of deferasirox. Fitting mathematical models to the experimental data indicated Fickian diffusion kinetics for all prepared materials.