Al3+ ion cross-linked interpenetrating polymeric network microbeads from tailored natural polysaccharides

Interpenetrating network (IPN) microbeads of sodium carboxymethyl locust bean gum (SCMLBG) and sodium carboxymethyl cellulose (SCMC) containing diclofenac sodium (DS), a non steroidal anti-inflammatory drug were prepared by single water-in-water (w/w) emulsion gelation process using AlCl3 as cross-linking agent in a complete aqueous environment. The influence of different variables like total polymer concentration, gelation time and crosslinker content on in vitro physico-chemical characteristics and drug release rate in different media was investigated. Drug loaded microbeads were evaluated through Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses. Scanning electron microscopy (SEM) micrograph of the beads suggested the formation of spherical particles. FTIR analysis indicated the stable nature of the drug in the blend microbeads. DSC and XRD analysis revealed amorphous state of drug after encapsulation. The drug release profile in acidic medium was considerably less in comparison to alkaline media. Formulations showed non-Fickian type transport mechanism. These tri-valent ion crosslinked beads not only improve drug encapsulation efficiency but also enhance drug release in phosphate buffer. (C) 2012 Elsevier B.V. All rights reserved.