Development of Interpenetrating Microspheres of Chitosan and Gum Arabic for Epigallocatechin Gallate to Enhance Colonic Delivery.

Epigallocatechin gallate is a potent phytomolecule with wide biological activity and is a class III drug. The therapeutic effect is limited, owing to poor stability and limited membrane permeability across the intestine. The aim of this study was to develop and evaluate colon-targeted microspheres of epigallocatechin gallate, using natural polymers. Water-in-oil emulsion crosslinking technique was used to prepare microspheres of epigallocatechin gallate using interpenetrating network of chitosan and gum acacia and glutaraldehyde was used as a crosslinking agent. Prepared microspheres were filled in capsules coated with Eudragit S100. The prepared microspheres were evaluated in vitro for preformulation studies, encapsulation efficiency, micromeritic properties, dissolution studies and stability studies. Fourier transform infrared spectroscopy and differential scanning calorimetry studies had proved that the drug and polymers are compatible. The good flow property of microspheres show that the microspheres are not aggregated. Scanning electron microscope micrographs of microspheres show a rough and folded surface morphology. The microspheres are spherical and uniform in shape. Formulations show good encapsulation efficiency. Formulation F1 to F6 show sustained release of drug for 10 h. The in vitro drug release of batch F1 to F6 were best explained by Higuchi models due to diffusion mechanism of drug release from polymeric matrix system. The selected formulation batch for a period of 3 mo at 40±2°/75±5 % RH show no significant changes. The current approach was helpful to develop polysaccharide based microspheres of epigallocatechin gallate to enhance colonic drug delivery. [ABSTRACT FROM AUTHOR]