FORMULATION AND EVALUATION OF RELEASE BEHAVIOR OF MICROSPHERES FROM CHITOSAN ENCAPSULATING PEFlOXACIN

Abstract

Poor solubility of chitosan at neutral pH and higher limits its application as an adsorption enhancer in the basic environment of the intestinal mucosa. The chitosan only can be dissolved in the acidic condition. To overcome these disadvantages of classical chitosan solution, it is essential to prepare chitosan derivatives which are water soluble around neutral pH. Microspheres were prepared from N-methylated chitosan by cross-linked with glutaraldehyde as the shell. The CS samples having different molecular weight were prepared by hydrolysis with 30 ml of 3 M HCl (30 ml/1 g of CS) at 60 °C. Structure and morphology was characterized with IR spectroscopy and scanning electron microscopy. Pefloxacin encapsulated in the microspheres was rapidly released into phosphate buffer solution (pH 7.4), whereas it was only slowly released in 0.1 M HCl (pH 1.2). The degree of swelling of microspheres at pH 7.4 was higher than that at pH 1.2. The release mechanism of the microsphere was proposed to be non-fickan diffusion through the swollen microspheres, and to be controlled by the Mw and the cross-linking density of shell. The current study explains about the release behavior of encapsulated drug.