Controlled drug release from a novel drug carrier of calcium polyphosphate/chitosan/aldehyde alginate scaffolds containing chitosan microspheres

Initial burst release of drugs is a major shortcoming which needs to be addressed in treating osteomyelitis by using drug delivery systems (DDS). The aim of this study was to develop a novel DDS for reducing initial burst release based on the combination of chitosan (CS) microspheres and calcium polyphosphate/chitosan/aldehyde alginate (CPP/CS/ADA) composite scaffolds. CS microspheres and CPP/CS/ADA composite scaffolds were characterized by FTIR spectroscopy, a laser particle size analyzer and SEM in order to reveal their composition, size distribution and surface morphology. Tetracycline hydrochloride (TC), as a model drug in the study, was encapsulated in CS microspheres, which further combined with CPP/CS/ADA composite scaffolds to form new DDS. Then the in vitro drug release was studied in detail. The kinetics of the drug release was also systematically studied. The results indicate that this new microspheres/scaffold compound system has a promising potential to reduce initial drug burst release effectively and prolong drug release time even for 30 days.