Abstract: To explore and develop scaffold for bone regeneration or tissue engineering with the capacity of controlled drug delivery, the feasibility of hydroxyapatite/polyurethane (HA/PU) scaffold containing drug-loaded microspheres for controlled drug delivery system was demonstrated. Ciprofloxacin hydrochlorid as a model drug was encapsulated in ethyl cellulose (EC) microspheres, which were subsequently incorporated into HA/PU composite scaffold to generate an antibiotic drug delivery system. The results show that EC microspheres are uniformly distributed in the HA/PU scaffold matrix and display no significant effect on the pore structure of the scaffold. Compared with incorporating ciprofloxacin hydrochlorid into scaffolds directly, embedding microspheres into scaffolds significantly reduces the initial burst drug release and extends the release time of drug delivery. In vitro drug delivery tests and antibacterial activity tests prove that drug-loaded microsphere/scaffold system has good drug delivery properties and effective antibacterial properties. These results suggest that the novel drug-loaded microsphere/ scaffold composites developed in this study is a good candidate scaffold with the function of bone repair and infection treatment for bone tissue engineering.

Key words: polyurethane, scaffold, microspheres, drug delivery, ethyl cellulose