Porous poly(L-lactide) membranes for guided tissue regeneration and controlled drug delivery: Membrane fabrication and characterization

With the aim of developing a new periodontal therapeutic modality, guided tissue regeneration (GTR), biodegradable barrier membranes composed of porous poly(L-lactide) (PLLA) films cast on poly(glycolide) (PGA) meshes were fabricated using an in-air drying phase inversion technique. PLLA was dissolved in methylene chloride-ethylacetate mixtures and cast on the knitted PGA meshes, followed by an air-drying process. The use of the three-component polymer solution (PLLA-methylene chloride-ethylacetate) was to generate porous substructures in the PLLA membranes during the solvent evaporation. The PGA meshes mechanically holding the PLLA membranes played an important role in forming the surface pores. Size and morphology of the pores were affected by the solvent composition of methylene chloride and ethylacetate. Regular pores were generated both at the surface and sublayer of the membranes. Flurbiprofen and tetracycline, used in periodontal therapy for their tissue regenerating effects, were incorporated in the membranes by adding the drugs in the PLLA solutions. The drug release kinetics mainly depended upon the hydrophobic-hydrophilic properties of the drugs and the porosity of the membranes regulated by the solvent composition of the PLLA solution. The release rate could be further controlled by loaded drug contents. The drug releasing porous PLLA membranes might be an effective therapeutic system in the treatment of periodontal disease.