Development and characterization of pH-sensitive locust bean gum-alginate microspheres for controlled release of ibuprofen

In this study, interpenetrating polymer network (IPN)microspheres, consisting of locust bean gum (LBG) and sodium alginate (NaAlg), were prepared by a water-in-oil (w/o) emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. These microspheres were loaded with ibuprofen (IBU), a nonsteroidal anti-inflammatory drug. The influence of formulation factors such as the LBG/NaAlg (w/w) ratio, the IBU loading percentage (w/w), the amount of cross-linker and cross-linking time on the particle size, the entrapment efficiency, and the release of IBU from the microspheres, were evaluated. The IPN microspheres were characterized using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Images of selected microspheres were determined using an optic microscope. The in vitro release of IBU from IPN microspheres was investigated at three pH values (1.2, 6.8 and 7.4) for 2 h, respectively. The release of IBU increased with the increase of the drug loading percentage (w/w), while it decreased with the increasing extent of cross-linking and with the increase in blend ratio (LBG/NaAlg). The release results indicated that IPN microspheres of LBG and NaAlg exhibited a more controlled release property than plain NaAlg microspheres. IBU release from the microspheres followed either Fickian transport or anomalous transport.