Formulation and characterization of pH sensitive drug carrier based on phosphorylated chitosan (PCS)

The new polyelectrolyte complex gel beads based on phosphorylated chitosan (PCS) were developed for controlled release of ibuprofen in oral administration. The PCS gel beads were readily prepared from soluble phosphorylated chitosan by using an ionotropic gelation with counter polyanion, tripolyphosphate (TPP), at pH 4.0. The beads were characterized by scanning electron microscopy (SEM) for morphological studies. The in vitro drug release behavior in various pH media was studied using ibuprofen as a model drug. Ibuprofen was highly loaded, around ∼90%, in the PCS gel beads. The release percents of ibuprofen from PCS gel beads were found to be increased as the pH of dissolution medium increased. The release rate of ibuprofen at pH 7.4 was noticeably higher than the release rate at pH 1.4 due to the ionization of phosphate groups and high solubility of ibuprofen at pH 7.4. These factors suggest that the PCS gel beads may be useful for controlled drug delivery system through oral administration by avoiding the drug release in the highly acidic gastric fluid region of the stomach.