Synthesis and characterization of ibandronate-loaded silica nanoparticles and collagen nanocomposites

Non-porous bare silica nanoparticles, amine modified silica nanoparticles and mesoporous particles, were evaluated as carriers for sodium ibandronate. The synthesized nanoparticles were characterized by SEM, TEM, DLS and porosity. Then, their capacity to incorporate a bisphosphonate drug (sodium ibandronate) and the in vitro release behavior was analyzed by capillary electrophoresis. Mesoporous and amine-modified particles showed higher levels of drug incorporation, 44.68 mg g(-1) and 28.90 mg g(-1), respectively. The release kinetics from the two types of particles was similar following a first order kinetics. However, when these particles were included into collagen hydrogels only mesoporous nanoparticles had a sustained release for over 10 days. The biocompatibility of mesoporous particles towards Saos-2 cells was also evaluated by the MTT assay observing an increase in cell viability for concentrations lower than 0.6 mg ml(-1) of particles and a decrease for concentrations over 1.2 mg ml(-1). Furthermore, when these particles were incubated with mesenchymal cells it was observed that they had the capacity to promote the differentiation of the cells with a significant increase in the alkaline phosphatase activity.