Design and characterization of dexamethasone phosphate -loaded microcapsules obtained by a double-emulsion method

Polymeric microcapsules are extensively investigated as drug delivery systems for a broad range of applications. In the present study, Dexamethasone-loaded carboxylated chitosan (CCS)/poly (vinyl alcohol) (PVA)-based microcapsules were prepared in view of their potential administration by inhalation for the treatment of lung diseases. The crosslinking between PVA and CCS was activated by [4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4methylmorpholinium chloride] (DMT-MM) and the FTIR results proved the formation of ester bonds between the two polymers. The sizes of the obtained microcapsules are influenced by the ratio between the polymers but also by the concentration of the DMT-MM activator. Moreover, the amount of PVA in the system has an important influence on swelling degree, encapsulation efficiency, drug release degree, biodegradation and protein adsorption. The sample with the highest amount of PVA has the highest crosslinking density and thus the lowest swelling degree and encapsulation efficiency. However, an encapsulation degree of 61.3% was obtained for the sample MCP-6 with the lowest PVA content. The same sample showed the lowest BSA adsorption. A controlled and sustained Dexamethasone release of around 90% was observed in PBS at pH 7.4 and 37 degrees C during 24 h. All the obtained samples were hemocompatibles and thus can be used as efficient drug delivery systems.

Automated summary

In this study, Dexamethasone-loaded carboxylated chitosan (CCS)/poly (vinyl alcohol) (PVA)-based microcapsules were prepared for inhalation administration in the treatment of lung diseases. The crosslinking between PVA and CCS was activated by DMT-MM and the FTIR results confirmed the formation of ester bonds. The size of the microcapsules was affected by the ratio between the polymers and the concentration of the DMT-MM activator. The amount of PVA in the system significantly influenced various properties, such as swelling degree, encapsulation efficiency, drug release, biodegradation, and protein adsorption. The microcapsules exhibited controlled and sustained drug release and were hemocompatible.