pH sensitive interpenetrating network microgels of sodium alginate-acrylic acid for the controlled release of ibuprofen

pH-Sensitive interpenetrating network (IPN) microgels (MGs) of sodium alginate (NaAlg) and acrylic, acid have been prepared by using water-in-oil (W/O) emulsion technique. The MGs were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffractometer (X-RD). The release of ibuprofen (113), an anti-inflammatory drug, from these MGs was studied in pH 1.2 and 7.4 media. MG net-work consists of NaAlg, which disintegrates in the intestinal fluid, while poly(acrylic acid) provides pH-sensitivity to the microgel network. The system developed in this study showed a pH-sensitivity for the release of 113, which was attributed to the diffusion controlled release of the drug through the surfaces of MGs that undergo disintegration after swelling, depending upon the chemical composition of MGs and pH of the medium. (c) 2005 Wiley Periodicals, Inc.