Papers by Author: Rangasamy Jayakumar

Abstract: N-Carboxymethyl chitosan (NCMC) is a water soluble derivative of chitosan. The NCMC beads were prepared by using ionotropic gelation process with the counter polyanion tripolyphoshate at pH 4.0 and characterized by scanning electron microscopy. The swelling behavior of the beads at different time intervals was monitored at different pH conditions. The in vitro drug release behavior in various pH solutions was studied using indomethacin as a model drug with two different concentrations (0.3 and 0.6% w/w). The release percent of indomethacin from NCMC beads was found to increase with increasing of pH in phosphate buffer solution medium due to the ionization of carboxymethyl group and high solubility of indomethacin in alkaline medium. These results indicated that the NCMC beads are useful for controlled drug delivery systems through oral administration by avoiding the drug release in the highly acidic gastric fluid region of the stomach.

Abstract: Phosphorylated chitosan (P-chitosan) was synthesized by means of graft copolymerization technique. The conjugate membranes were prepared from oxidised starch and Pchitosan using reductive alkylation crosslinking. The synthesized membranes were characterised by FT-IR. In order to characterize degradation behaviour of this conjugated system, the membranes were incubated in enzyme solutions of alpha-amylase and lysozyme as well as a physiological saline solution (PBS) used as control solution. In PBS, low starch containing membranes (0.16-0.38 weight (starch)/weight (P-chitosan), (ws/wc)) and control membranes have not showed significant change in their weight during two months of incubation. High starch containing membranes (0.73-1.04 ws/wc) indicated less than 20 % weight loss after this period. After α-amylase incubation, a distinct degradation behaviour was observed from starch-P-chitosan membranes. The degradation of the conjugate membranes was found to be fast with increasing starch content. Weight losses between 20 to 55 % were detected for the lowest (0.16 ws/wc) starch and highest (1.04 ws/wc) starch containing membranes, respectively. In the lysozyme degradation study, the conjugate membranes were not degraded by enzymatic activity and the weights of membranes were seen to be increased about 20 % because of swelling. The control membranes showed gradual weight loss in enzyme solutions. These results indicated the lysozyme degradation of starch-free P-chitosan membranes and inhibition of degradation P-chitosan by highly conjugated starch molecules.