Polyphosphazene membranes and microspheres in periodontal diseases and implant surgery

Membranes or microcapsules made from polyphosphazenes bearing amino acid si de groups are proposed for the treatment of periodontal diseases. Polyphosp hazene membranes, prepared with alanine ethyl ester and imidazole in the mo lar ratio of 80:20 as phosphorus substitutents, gave a degradation rate tha t corresponded to the healing of the bone defect. These membranes were much more successful in promoting healing of rabbit tibia defects than polytetr afluoroethylene membranes. Antibacterial or anti-inflammatory drugs, useful in periodontal tissue regeneration, could be entrapped in the polyphosphaz ene membranes and released both in vitro and in vivo at a rate that ensured therapeutic concentrations in the surrounding tissue. Polyphosphazene micr ospheres, prepared with phenylalanine ethyl eater as a phosphorus substitue nt and loaded with succinylsulphathiazole or naproxen, were also obtained. The kinetics of release from these matrices were very convenient in yieldin g local concentrations of the two drugs that are useful per se or when mixe d with hydroxyapatite for better bone formation. (C) 1998 Elsevier Science Ltd. All rights reserved.