In vitro analysis of a local polymeric device as an alternative for systemic antibiotics in Dentistry

Abstract The development of a biodegradable material with antimicrobial properties for local applications is required in the prevention and treatment of infectious diseases. The objective of this study was to produce blends of poly-L-lactide acid (PLLA) synthetic polymer associated with several antimicrobials, as an alternative in the prevention and treatment of infections, as well as to evaluate its cytotoxicity, release of antimicrobials and inhibit bacteria growth. Blends of PLLA added with 20% Amoxicillin, Metronidazole, Clindamycin or Azithromicyn were used to produce Films (F) or Meshs (M) by casting and electrospinning methods, respectively. Standardized discs of the films and meshs were stored in buffer solutions (pH 5 or 7.4) and aliquots were analyzed by high performance chromatography (HPLC) during 168 hours. Cytotoxicity on human gingival fibroblasts was tested after 24, 48 and 72h by MTT reaction. The antimicrobial capacity was determined against P. gingivalis and S. pyogenes. The specimens were weighed after 3 and 6 months of storage for degradation analysis. SEM was performed to control interfaces and degradation. Antimicrobials presented a continuous and exponential drug release. Analysis showed that both M and F were able to inhibit S. pyogenes and P. gingivalis growth, indicating the release of active antimicrobial agents. The products were not toxic to the fibroblasts. Amoxicillin-film showed more degradation than PLLA at both pHs (p < 0.05), whereas Azithromycin-meshes were more degraded than PLLA at pH 7.4 (p < 0.05). PLLA association with antimicrobials is biocompatible and may represent a potential tool for the local delivery of antimicrobials.摘要 为实现感染性疾病的预防与治疗，亟需开发适用于局部应用的抗菌可生物降解材料。本研究旨在制备聚-L-乳酸（poly-L-lactide acid, PLLA）合成聚合物与多种抗菌剂的共混物，作为感染防控与治疗的替代方案，并评价其细胞毒性、抗菌剂释放特性及抑菌能力。本研究分别采用浇铸法与静电纺丝法，将添加20%阿莫西林、甲硝唑、克林霉素或阿奇霉素的PLLA共混物制备为薄膜（F）与网状材料（M）。将标准化的薄膜与网状材料圆盘置于pH为5或7.4的缓冲溶液中储存，并在168小时内采用高效液相色谱法（high performance chromatography, HPLC）对取样液进行检测分析。采用MTT法在24、48和72小时时点，检测其对人牙龈成纤维细胞的细胞毒性。针对牙龈卟啉单胞菌与化脓性链球菌测定其抗菌活性。将试样储存3个月与6个月后进行称重，以开展降解分析；同时采用扫描电子显微镜（scanning electron microscope, SEM）表征材料界面与降解情况。结果显示，抗菌剂呈现出持续且指数级的药物释放特征。分析表明，网状材料与薄膜均能抑制化脓性链球菌和牙龈卟啉单胞菌的生长，提示抗菌剂已释放且保持生物活性。该共混产物对成纤维细胞无细胞毒性。在两种pH条件下，阿莫西林薄膜的降解程度均高于纯PLLA（p < 0.05）；而在pH 7.4条件下，阿奇霉素网状材料的降解程度高于纯PLLA（p < 0.05）。PLLA与抗菌剂的共混体系具备良好的生物相容性，有望成为抗菌剂局部递送的潜在载体。