Abstract

Background: Metronidazole (MTZ) is active against anaerobic bacteria; therefore, MTZ-loaded liposomes represent a potential approach to enhance biofilm penetration, prolong drug action, and improve the efficacy of local treatment. Objective: This study aimed to optimize an in vitro biofilm formation model of Porphyromonas gingivalis (P. gingivalis) and to evaluate the antibiofilm activity of MTZ-loaded liposomal gel against this bacterium.

Materials and Methods: P. gingivalis ATCC 33277, raw MTZ, standard MTZ, and related chemicals were used in this study. The effects of culture medium and incubation time on the biofilm-forming ability of P. gingivalis, as well as the antibiofilm activity of MTZ-loaded liposomal gel, were investigated.

Results: An in vitro biofilm formation model of P. gingivalis was successfully established, with suitable conditions consisting of BHI medium supplemented with hemin 5 µg/mL and vitamin K 1 µg/mL, followed by anaerobic incubation at 37°C for 48 or 72 hours. P. gingivalis ATCC 33277 was sensitive to both MTZ Liposome gel and raw MTZ gel, with MIC values of < 0.03 µg/mL and 0.06 µg/mL, respectively. Both formulations significantly reduced preformed biofilms at MTZ concentration of 0.24 µg/mL and almost completely inhibited biofilm formation at MTZ concentration of 0.24 µg/mL after 48 h and 0.48 µg/mL after 72 h.

Conclusion: These findings provide preliminary in vitro evidence to support further studies on periodontal disease.