Saeed Zajforoushan Moghaddam

In this study, mussel-inspired chemistry, based on catechol-amine reactions, was adopted to develop self-cross-linkable chitosan-alginate (Chi-Alg) complexes. To do so, the biopolymers were each substituted with ∼20% catechol groups (ChiC and AlgC), and then four complex combinations (Chi-Alg, ChiC-Alg, Chi-AlgC, ChiC-AlgC) were prepared at the surface and in bulk solution. Based on QCM-D and lap shear adhesion tests, the complex with catechol only on Chi (ChiC-Alg) did not show a significant variation from the control complex (Chi-Alg). Conversely, the complexes with catechol on alginate (Chi-AlgC and ChiC-AlgC) rendered a self-cross-linking property and enhanced cohesive properties.

In this study, dopamine-assisted deposition combined with layer-by-layer assembly was investigated as an efficient method for preparing coatings with tunable thickness, roughness, and functional properties. By this method, one can first benefit from the versatile chemistry of dopamine allowing the co-deposition of various functional materials, for example, polymers, ions, and nanoparticles, within the coating. Moreover, the layer-by-layer approach allows tuning the coating thickness and surface roughness, as well as varying the chemical composition of the coating in the vertical direction. Herein, we demonstrated the benefits of using this method in fabricating both single- and multi-component coatings.

The biggest challenge in oral delivery of anti-inflammatory drugs such as 5-aminosalicylic acid (5-ASA) is to (i) prevent rapid absorption in the small intestine and (ii) achieve localized release at the site of inflammation in the lower gut, i.e., the colon. Here, we present an advanced biopolymeric coating comprising of tannic-acid-functionalized zein protein to provide a sustained, colon-targeted release profile for 5-ASA and enhance the mucoadhesion of the dosage form via a mussel-inspired mechanism. To enable localized delivery and provide high local concentration, 5-ASA is loaded into the microfabricated drug carriers (microcontainers) and sealed with the developed coating. The functionality and drug release profile of the coating are characterized and optimized in vitro, showing great tunability, scalability, and stability toward proteases. Further, ex vivo experiments demonstrate that the tannic acid functionalization can significantly enhance the mucoadhesion of the coating, which is followed up by in vivo investigations on the intestinal retention, and pharmacokinetic evaluation of the 5-ASA delivery system. Results indicate that the developed coating can provide prolonged colonic delivery of 5-ASA. Therefore, the here-developed biodegradable coating can be an eco-friendly substitute to the state-of-the-art commercial counterparts for targeted delivery of 5-ASA and other small molecule drugs.