Chitosan coated alginate -carrageenan particulate systems for sustained release of naproxen

The purpose of this work was to develop sustained release particulate systems of naproxen, an anti-inflammatory agent by using natural polysaccharides polymers, such as sodium alginate, chitosan and carrageenan. Naproxen -loaded chitosan coated alginate microspheres were prepared by ionotropic gelation methods using various combinations of chitosan and Ca2+ as cations and alginate & carrageenan as anion. In-vitro drug release & pattern of the microspheres were studied at pH 1.2 and 7.4. Fourier transform infra-red (FTIR) spectrometry, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), x-ray diffraction (XRD) were also applied to investigate the physicochemical characteristics of the drug in formulations. The surface morphology, size, and drug loading of the microspheres varied with increment in the concentration of chitosan, alginate and calcium chloride in the gelation medium and curing time was observed. The microspheres prepared with chitosan coated alginate shows 77% of the drug release within 6 h, whereas microspheres prepared with carrageenan slowed the drug release to 60 %. The release data from all the formulation was found to fit in first-order kinetics model. Data’s from characterisation studies indicate that there was no change in the physical state of the drug in the formulations. It is concluded that the release of the naproxen could be prolonged by using mixture with carrageenan in chitosan coated alginate microspheres.