Background: Periodontitis is an inflammatory disease with a bacterial etiology that affects the supporting structures of the teeth and is a major cause of tooth loss. The objective of this study was to investigate the drug loading and in vitro release of minocycline from novel calcium polyphosphate microspheres intended for use in treating periodontitis. Methods: Calcium polyphosphate coacervate, produced by a precipitation reaction of calcium chloride and sodium polyphosphate solutions, was loaded with minocycline and subsequently used to produce microspheres by an emulsion/solvent extraction technique. Microspheres classified by size were subjected to a 7-day elution in a Tris-buffer solution under dynamic conditions. The physicochemical characteristics of the drug-loaded microspheres were investigated using scanning electron microscopy, particle size analysis, Phosphorus-31 Nuclear Magnetic Resonance spectroscopy, and Inductively Coupled Plasma Optical Emission Spectroscopy. Drug loading and release were determined using ultraviolet -visible (UV/VIS) spectrophotometry. Results: Minocycline-loaded calcium polyphosphate microspheres of varying size were successfully produced, with small and large microspheres having volume mean diameters of 22 ± 1 µm and 193 ± 5 µm, respectively. Polyphosphate chain length and calcium to phosphorus mole ratio remained stable throughout microsphere production. Drug loading was 1.64 ± 0.16, 1.35 ± 0.55, and 0.84 ± 0.14 weight% for the coacervate and large and small microspheres, respectively, corresponding to mean encapsulation efficiencies of 81.7 ± 12.2 % and 50.9 ± 3.9 % for the large and small microspheres. Sustained drug release was observed in vitro over a clinically relevant 7-day period, with small and large microspheres exhibiting similar elution profiles. Antibiotic release generally followed microsphere degradation as measured by Ca and P ion release. Conclusions: This study demonstrated successful drug loading of calcium polyphosphate microspheres with minocycline. Furthermore, in vitro sustained release of minocycline over a 7-day period was observed, suggesting potential utility of this approach for treating periodontitis.

中文翻译：

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负载米诺环素的聚磷酸钙玻璃微球作为治疗牙周炎的潜在药物递送剂

背景：牙周炎是一种炎症性疾病，其细菌病因会影响牙齿的支撑结构，是导致牙齿脱落的主要原因。本研究的目的是研究用于治疗牙周炎的新型聚磷酸钙微球中米诺环素的载药量和体外释放情况。方法：通过氯化钙和多聚磷酸钠溶液的沉淀反应产生的多聚磷酸钙凝聚层负载米诺环素，随后通过乳液/溶剂提取技术用于生产微球。按大小分类的微球在动态条件下在 Tris 缓冲溶液中进行 7 天洗脱。使用扫描电子显微镜研究了载药微球的理化特性，粒度分析、Phosphorus-31 核磁共振光谱和电感耦合等离子体发射光谱。使用紫外-可见光(UV/VIS)分光光度法测定载药量和释放量。结果：成功制备了不同尺寸的负载米诺环素的聚磷酸钙微球，大小微球的体积平均直径分别为 22 ± 1 µm 和 193 ± 5 µm。多磷酸盐链长和钙磷摩尔比在整个微球生产过程中保持稳定。凝聚层和大小微球的载药量分别为 1.64 ± 0.16、1.35 ± 0.55 和 0.84 ± 0.14 重量%，对应于大微球和小球的平均包封效率分别为 81.7 ± 12.2 % 和 50.9 ± 3.9 %。在临床相关的 7 天期间，在体外观察到持续的药物释放，大小微球表现出相似的洗脱曲线。抗生素释放通常跟随微球降解，通过 Ca 和 P 离子释放测量。结论：本研究证明了多磷酸钙微球与米诺环素的成功载药。此外，观察到米诺环素在 7 天的体外持续释放，表明这种方法治疗牙周炎的潜在效用。该研究证明了多磷酸钙微球与米诺环素的成功载药。此外，观察到米诺环素在 7 天的体外持续释放，表明这种方法治疗牙周炎的潜在效用。该研究证明了多磷酸钙微球与米诺环素的成功载药。此外，观察到米诺环素在 7 天的体外持续释放，表明这种方法治疗牙周炎的潜在效用。