Development and optimization of Fe³⁺-crosslinked sodium alginate-methylcellulose semi-interpenetrating polymer...

In this study, ionically crosslinked beads of sodium alginate (NaAlg) and methylcellulose (MC) were prepared as semi-interpenetrating polymer networks (semi-IPN) in the size range of 1.97 ± 0.09-1.22 ± 0.13 mm by crosslinking with FeCl₃ and loaded with ibuprofen (IBU), which is a nonsteroidal anti-inflammatory drug. The highest 93.33% entrapment efficiency of IBU was achieved, and the drug release behaviors, mean particle size, and entrapment efficiency of beads were investigated in terms of the polymer composition, a ratio of ibuprofen to polymer, exposure time to crosslinker, and concentration of the crosslinking agent. Semi-IPN formulations prepared were also characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X-ray Diffraction (X-RD), and scanning electron microscopy (SEM). It was observed that IBU-loaded beads displayed better release performance with an increase amount of NaAlg in the structure. Finally, the optimum IBU release was obtained as 93.9% for beads containing 66.7% (w/w) NaAlg, 33.3% (w/w) MC, IBU/polymer ratio of 1/4, FeCl₃ concentration of 0.1 M, and crosslinking time of 90 min. The in vitro release rate was fitted to five empirical equations, and the diffusion exponent n, which indicated that the release mechanism of IBU from beads followed the Anomalous and Case II transport mechanism.