Dec 2017 DOI 10.14302/issn.2640-6403.jtrr-17-1840
Rogina AnamarijaCorresponding author
Faculty of Chemical Engineering and Technology, University of Zagreb
Up till now, chitosan has confirmed its versatile application in skin, cartilage and bone tissue engineering, as well as in drug delivery applications. This study is focused on enzymatic degradation of porous chitosan structures usually designed for mentioned purposes. In vitro degradation was monitored during four weeks of incubation at physiological temperature and in two different media, phosphate buffer saline solution and water. The scaffolds were characterised before and after enzymatic degradation using scanning electron microscopy and infrared spectroscopy with Fourier transformations (FTIR). According to the gravimetric analysis, higher weight loss of chitosan scaffolds was observed in buffered medium with respect to the water. The results implied that the total weight loss obtained in buffer involves physical dissolution of chitosan and lysozyme cleavage of glycoside bond. Importantly, FTIR identification of chitosan scaffolds after enzymatic degradation indicated the absence of lysozyme activity in water, indicating that weight loss is a result of the chitosan dissolution. This finding greatly impacts design of degradation experiments and characterisation of degradation behaviour of chitosan-based materials utilised as implants or drug delivery systems.
Nov 2013 DOI 10.14302/issn.2328-0182.japst-12-119
Nath BipulCorresponding author
Department of Pharmaceutical Sciences, Dibrugarh University, 786004, Assam, India
The purpose of the research is to evaluate Sterculiaurens gum as a carrier for oral colon targeted drug delivery system. Sterculia gum has been reported to have wide pharmaceutical applications such as tablet binder, disintegrant, gelling agent and as a controlled release polymer, but it has not been exploited as colon targeting carrier. For evaluation as a carrier for colonic delivery of drugs characterization of gum was done. Microflora degradation studies of gum were conducted in phosphate buffer solution (PBS) pH 7.4 containing rat caecal content under anaerobic environment. Solubility, swelling index, viscosity and pH of the polymer solution were determined. Different formulation aspects considered were: gum concentration (10–40%), concentration of citric acid (10–30 %) on swelling index and in-vitro drug release. The results of the isothermal stress testing (IST) shows no degradation of samples of model drug, azathioprine, in the drug polymer mixture and the core tablet excipients. DSC and FT-IR study has proved the compatibility of the drug with Sterculia gum and other tablet excipients. Microflora degradation study revealed that Sterculia gum can be used as tablet excipient for drug release in the colonic region by utilizing the action of enterobacteria. Sterculia gum exhibits premature drug release in the upper GIT without enteric coating and may not reach to the colonic region. From the study, Sterculia gum as colon targeting carrier is possible via coating with chitosan/Eudragit mixed blend polymers which would provide acid as well as intestinal resistance; but undergo enzymatic degradation once it reaches the colon.