Chitosan coated- and uncoated-microspheres of sodium carboxymethyl cellulose/polyvinyl alcohol crosslinked with ferric ion: flurbiprofen loading and in vitro drug release study

The present work aimed to develop of chitosan coated and uncoated microspheres of sodium carboxymethyl cellulose (NaCMC) and polyvinyl alcohol (PVA) crosslinked with Fe3+ ions. The microspheres were coated with chitosan to enhance their mechanical properties and prevent the burst effect of flurbiprofen (FBP). The chitosan coated NaCMC/PVA microspheres loaded with different drug-to-polymer ratios of FBP were prepared by changing the experimental variables such as NaCMC/PVA (w/w) ratio, concentration of cross-linker, cross-linking time, and enteric coating. The influence of this formulation factors was evaluated for entrapment efficiency, particle size, and in vitro release of FBP from the microspheres in pH 1.2 HCl and 7.4 buffer media for both enteric coated and uncoated microspheres. Structural features of the microspheres were characterization by differential scanning calorimetry (DSC), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The chitosan coated and uncoated NaCMC/PVA microspheres showed different degrees of swelling in water. The microspheres exhibited entrapment efficiency from 21.96 to 40.22% and particle size in the range 3.8–9 µm. The release results indicated that the coated microspheres displayed a slower release and less burst effect than uncoated microspheres.