Antibiotic medications have been found to hinder the success of regenerative endodontic treatment due to the rapid degradation of the drug, and the acidic nature of ciprofloxacin (CIP) can be harmful to stem cells of the apical papilla (SCAPs), the cells responsible for regeneration. In this study, a nanocarrier system was used for controlled drug release for longer drug activity and less cytotoxicity to the cells. CIP was loaded in poly (ethylene glycol) methyl ether-block-poly (lactide-co-glycolide) (PEG–PLGA) nanoparticles (NPs) with an ion-pairing agent. The NPs demonstrated a monodispersed spherical morphology with a mean diameter of 120.7 ± 0.43 nm. The encapsulation efficiency of the CIP-loaded PEG–PLGA NPs was 63.26 ± 9.24%, and the loading content was 7.75 ± 1.13%. Sustained CIP release was achieved over 168 h and confirmed with theoretical kinetic models. Enhanced NP bactericidal activity was observed against Enterococcus faecalis. Additionally, CIP-loaded PEG–PLGA NPs had a low cytotoxic effect on SCAPs. These results suggest the use of a nanocarrier system to prolong the antibiotic activity, provide a sterile environment, and prevent reinfection by the bacteria remaining in the root canal during regenerative endodontic treatment.

Key success for regenerative endodontics is an effective removal of bacteria inside the root canal during the treatment. Ciprofloxacin (CIP) is one of the triple antibiotics commonly used as the root canal medicament. However, the rapid clearance of antibiotics causes bacterial reinfection. Nanoparticles (NPs) provide an alternative approach for antibiotics delivery system to improve the drug stability and release control. In the previous study, modified dextran was successfully formed the ester linkage with vinyl decanoate via lipase-catalyzed transesterification. The amphiphilic dextran, dextran-decanoate (Dex-D), has been synthesized with the degree of substitution of 83-88% and were applied for CIP-loaded nanoparticles. The suitable technique for producing antibiotic carriers considering by size, shape, and drug encapsulation efficiency was investigated in this work. The preparation methods were compared between nanoprecipitation and solid-in-oil-in-water (s/o/w) ion pairing technique. We found that the obtained Dex-D nanoparticles had stable monodispersed with spherical shape in both techniques. However, Dex-D nanoparticles formed by s/o/w ion pairing technique provided smaller size with better encapsulation efficiency. The antimicrobial activity of CIP-loaded Dex-D nanoparticles against oral pathogens showed satisfactory outcome with the MIC equal to 0.7 μg/mL. Also, the compatibility of nanoparticles and dental stem cells was observed in this work.