Preparation of Mesalazine-Clay Composite Encapsulated Alginate (MCA) Bead for Targeted Drug Delivery: Effect of Composite Content and CaCl2 Concentration

Abstract

Mesalazine is a colon target drug used extensively for the treatment of Crohn&apos;s disease. To avoid the side effects as well as insufficient absorption of the drug, targeted release of mesalazine at the site of action, small bowel or colon, should be needed. In the present study, mesalazine-clay composite encapsulated alginate (MCA) beads are synthesized with various concentrations of mesalazine-clay composite (MCC) and cross-linker (CaCl2) for targeted drug delivery. Because of mesalazine intercalation in montmorillonite (MMT) clay and pH-sensitive swelling property of alginate polymer in alkaline condition, MCA beads exhibited a high mesalazine loading efficiency (ae9%) and selective mesalazine release in intestinal condition. The preparation conditions of MCA beads considerably affected drug entrapment efficiency, swelling property, and drug release profile. In particular, increase in MCC content in MCA beads lead to significant improvement in mesalazine loading efficiency and prevented immediate destruction caused by over-swelling of MCA beads in intestinal conditions (pH 7.4). A denser alginate network formed by the immobilization of MCC prevents mesalazine loss in intestinal condition and increases the stability of MCA beads against over-swelling. Finally, an in vitro release test revealed that MCA beads (1 g MCC content, cross-linked with 1 M CaCl2) not only prevented mesalazine release in the gastric condition (< 8%) but also retarded mesalazine release in the intestinal condition. The comprehensive results of this study will provide practical insights into the use of MCA beads for targeted drug delivery.