Mucoadhesive micro-composites: Chitosan coated halloysite nanotubes for sustained drug delivery.

It was aim of this study to synthesize micro-composites comprising halloysite nanotubes (HNTs) and the cationic polymer chitosan as mucoadhesive sustained release drug delivery system. Micro-composites were characterized for preparation yield, size, micromeritic properties and swelling behavior. Chemical composition of micro-composites was characterized by FTIR, XRD and TGA. Scanning electron microscopy (SEM) was used to study their surface morphology. Micro-composites were studied for adhesion on intestinal mucosa as well as for release behavior of metoclopramide hydrochloride used as model drug. Preparation yield was found to be in the range of 35.14 ± 1.5-53.97 ± 5.23%. Micro-composites exhibited a mean size range of 0.151 ± 0.49 μm. SEM showed a spherical shape with rough curved porous surface. Micro-composites exhibited excellent flowability and maximum swelling at acidic pH. XRD results showed crystalline nature of micro-composites. HNTs/micro-composites with highest concentration of chitosan displayed maximum adherence of 89 ± 1.79% on intestinal mucosa after 3 h. Drug release recorded was 66.8% at pH 1.2 and 46.7% at pH 5.5 within 25 h. Chitosan coated HNTs showed remarkable mucoadhesion and sustained release of metoclopramide proving their suitability as mucoadhesive drug delivery system.