Antimicrobial and anti-inflammatory potential of thermoresponsive in situ gel loaded with metronidazole microsponges for localized treatment of periodontitis

Periodontitis is an inflammatory disease that goes deeply into the tissues, causing loss of alveolar bone and supporting connective tissues. Severe periodontal diseases are estimated to affect around 19% of the global adult population, representing more than 1 billion cases worldwide. Metronidazole (MTZ) is frequently used to inhibit anaerobic bacteria in periodontal disease. This study aimed to fabricate MTZ-eudragit microsponges (MSPs) and then loading them into gel to evaluate its sustained local action in the buccal cavity. To optimize MTZ- MSPs, different variables such as drug:polymer ratio, polymer:solvent ratio and stirring rate were studied. characterization of MSPs, such as thermal behavior, surface morphology, particle size and drug release, were studied. The optimized MSPs were spherical with numerous pores on the surface (sponge-like particles). These optimized MSPs also showed high entrapment efficiency (87 ± 1%), mean particle size of 45 ± 1 µm (PDI 0.2 ± 0.1) and sustained drug release (57 ± 1% through 12 hours). The optimized MSPs were then incorporated into a thermoresponsive gel (20% PF-127/2% PF-68/0.5% HPMC). MSPs-containing gel was free flowing at room temperature and gel in the buccal cavity, retarding drug release and enhancing the mucoadhesion and antibacterial activity. studies on rats revealed that this gel is an effective and innovative approach to treating periodontitis. Conclusion, MSPs-loaded gel is a promising vehicle for MTZ to treat periodontitis.