Encapsulation of antibiotics in poly(ethylene glycol)‐block‐poly(L‐lactide) for delivery in dentin tubules during root canal treatment (733.4)

Abstract

Aim: To encapsulate an antibiotic in oral applications with PEG/PLA‐block copolymer into microparticles for infected dentin tubules. To maintain drug release for extended periods to prevent bacterial regrowth after root canal treatment. Methodology: Drug encapsulation was carried out through an oil‐water emulsion‐solvent evaporation method. In summary, the PEG/PLA copolymer and the oral drug were dissolved in an oil phase (dichloromethane), which was combined with an aqueous (polyvinyl alcohol and de‐ionized water). The solution was stirred, centrifuged, washed, and lyophilized. Particle size was determined using digital microscopy. Antimicrobial effectiveness was assessed in vitro by placing small amounts of encapsulated particles on bacterial agar plate cultures and monitoring growth inhibition. Results: Encapsulated particles ranged in size from 300 nm to 1.0 m. A 2 week bacterial inhibition test showed that the particles exhibited zones of inhibition between 3 mm and 5 mm. Conclusion: The proposed method with the PEG/PLA copolymer encapsulates the oral antibiotic producing particles with size distribution that may penetrate the dentinal tubules (2.5 m in diameter). Bacterial inhibition tests showed that the particles inhibited bacterial growth after 2 weeks. Ongoing bacterial inhibition tests will determine the release profile of the microparticles.