Preparation of sustained-release composite coating formed by dexamethasone and oxidated sodium alginate

Inflammatory reaction and thrombosis are the unsolved main problems of non-coated biomaterials applied in cardiac surgery. In the present study, a series of sustained composite coating was prepared and characterized, such as in the chemical modification of polyvinyl chloride (PVC) for applications in cardiac surgery and the assessment of the biological property of modified PVC. The composite coatings were mainly formed by dexamethasone (DXM) and oxidated sodium alginate (OSA) through ionic and covalent bond methods. The biocompatibility and hemocompatibility of the coating surface were evaluated. Scanning electron microscopy analysis of the surface morphologies of the thrombus and platelets revealed that DXM-OSA coating improved the antithrombogenicity and biocompatibility of PVC circuits, which were essential for cardiac pulmonary bypass surgery. Evaluation of in vitro release revealed that the DXM on group PPC was gradually released in 8 h. Thus, DXM that covalently combined on the PVC surface showed sustained release. By contrast, DXM on groups PPI and PPD was quickly or shortly released, suggesting that groups PPI and PPD did not have sustained-release property. Overall, results indicated that the DXM-OSA composite coating may be a promising coating for the sustained delivery of DXM.