pH-sensitive free AgNPs composite and nanocomposite beads based on starch as drug delivery systems

In this work, a novel free AgNPs composite, St-A-E/M, and nanocomposite beads, St-A-E/M-Ag, as a novel drug carrier were successfully prepared and used as controlled-release drug delivery systems for methyl prednisolone as a model drug. The structure of the resulted materials was identified using UV-Vis, SEM, EDX, XRD, FTIR, TEM, DLS, AFM and TGA/DTG spectroscopic techniques. The TEM and DLS results demonstrated that the incorporated AgNPs in the polymer matrix were spherical with diameters ranging from 50 to 111 nm. The influence of contact time, temperature, content of initial pH and Ag nanoparticles on the load and release behaviors of drug model was investigated under static conditions. The results indicated that the % release of drug model from the nanocomposite in different amounts of AgNPs was rather higher in comparison with the corresponding free-NPs composite. On the other hand, the results showed that the % release of drug increased by the increase in AgNPs content until 3.3% (V/V) in the polymer matrix, whereas that released beyond it was decreased. The maximum of release was also found within 9 h and at pH 7.4 for the nanocomposite. Furthermore, different release kinetic was employed for the description of the release process. Also, the nanocomposite exhibited higher antibacterial activity compared to the corresponding free-NPs composite.