A tunable and injectable local drug delivery system for personalized periodontal application

In periodontal treatment, patient differences in disease phenotype and treatment responses are well documented. Therefore, therapy duration and dosage should be tailored to the requirements of individual patients. To facilitate such personalized medication, a tunable and controllable system is needed to deliver drugs directly into the diseased periodontal pockets. The current study established a system to achieve different drug release rates and periods by incorporating bioactive agents into poly(lactic-co-glycolic acid) (PLGA) microspheres dispersed into a novel thermo-reversible polyisocyanopeptide (PIC) hydrogel. Specifically, two drugs, i.e. doxycycline and lipoxin, were separately loaded into acid-terminated and ester-capped PLGA by electrospraying. Different formulations were developed by loading the two kinds of PLGA microspheres with different mass ratios in the PIC gels. The results demonstrated that the PIC-PLGA vehicle exhibited appropriate injectability, long-term structural stability, and no obvious in vivo inflammatory response for the desired clinical application. Furthermore, the release profiles of drugs could be manipulated by adjusting the loaded mass ratio of acid- and ester- terminated PLGA microspheres in the PIC gels. The more ester-capped PLGA was used, the slower the release rate and the longer the release period, and vice versa. Additionally, the released drugs still preserved their bio-efficacy. This PIC-PLGA system can be further developed and tested in translational studies to demonstrate the final clinical benefit.