RESUMO
Background and objective: Tetracycline and its derivatives, combined with calcium phosphates, have been proposed as a delivery system to control inflammatory processes and chronic infections. The objective of this study was to evaluate the microspheres of alginate encapsulated minocycline-loaded nanocrystalline carbonated hydroxyapatite (CHAMINO) as a biomimetic device to carry out target-controlled drug delivery for alveolar bone repair. Methods: CHAMINO microspheres were implanted in a rat central incisor socket after 7 and 42 days. New bone was formed in both groups between 7 and 42 days of implantation. However, the bone growth was significantly higher for the CHAMINO microspheres. Results: The minocycline (MINO) loading capacity of the nanocrystaline carbonated hydroxyapatite (CHA) nanoparticles was 25.1±2.2 µg MINO/mg CHA for adsorption over 24 hrs. The alginate microspheres containing minocycline-loaded CHA were biologically active and inhibited the Enterococcus faecalis culture growth for up to seven days of the MINO release. An osteoblastic cell viability assay based on the resazurin reduction was conducted after the cells were exposed to the CHAMINO powder and CHAMINO microspheres. Thus, it was found that the alginate extracts encapsulated the minocycline-loaded CHA microspheres and did not affect the osteoblastic cell viability, while the minocycline-doped CHA powder reduced the cell viability by 90%. Conclusion: This study concluded that the alginate microspheres encapsulating the minocycline-loaded nanocrystalline carbonated hydroxyapatite exhibited combined antibacterial activity against Enterococcus faecalis with cytocompatibility and osteoconduction properties. The significant improvement in the new bone formation after 42 days of implantation suggests that the CHAMINO microsphere has potential in clinical applications of bone regeneration.
Assuntos
Alginatos/química , Regeneração Óssea/efeitos dos fármacos , Carbonatos/química , Durapatita/química , Microesferas , Minociclina/farmacologia , Nanopartículas/química , Animais , Antibacterianos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Enterococcus/efeitos dos fármacos , Humanos , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Osteoblastos/efeitos dos fármacos , Ratos Wistar , Difração de Raios XRESUMO
O presente trabalho teve por meta revisar a literatura pertinente à aplicaçäo do antibiótico tetraciclina na periodontia. Foram considerados aspectos relativos às propriedades especiais farmacológicas, efeito antibacteriano, propriedades especiais da droga, efeitos adversos e aplicaçöes clínicas. Concluiu-se com o estudo que os benefícios clínicos obtidos com a utilizaçäo da tetraciclina foram devidos a uma combinaçäo da propriedade antimicrobiana com propriedades especiais da droga. Atençäo especial foi dada para a alta concentraçäo no fluido gengival, boa substantividade, propriedades antiinflamatórias, capacidade inibitória de colagenases intersticiais e outras enzimas e inibiçäo da reabsorçäo óssea. A tetraciclina apresentou efetividade contra o actinobacillus actinomycetemcomitans (Aa), sendo assim relevante no tratamento da periodontite juvenil localizada (PJL). Entretanto, outros trabalhos säo necessários na seleçäo de pacientes que possam obter benefícios com a terapia adjunta com a tetraciclina
