Designing nanoparticle-based inhaled antibiotics for the treatment of cystic fibrosis associated biofilms and infections and in vivo studies in a rat model.

在第一阶段，在配制过程中使用系统变化，我们开发并优化了聚酯聚合物的不同微米和纳米颗粒制剂，其中具有抗假单胞菌活性的不同抗生素被稳定有效地包封。对颗粒的理化特性进行了广泛的表征，并开发了储存形式。使用体外试验，我们能够证明，非包封的妥布霉素表现出对铜绿假单胞菌和洋葱伯克霍尔德氏菌的生物膜没有活性。相比之下，纳米颗粒包封恢复了妥布霉素对这些生物膜的活性。聚（D，L-丙交酯-共-乙交酯）-聚[（D，L-丙交酯-共-乙交酯）-共-聚乙二醇]（PEG-PLGA）-包封的妥布霉素对生物膜的有效性比游离药物或两种组分的混合物高1000倍。包封的妥布霉素的有效浓度甚至低于妥布霉素静脉内治疗期间测量的浓度。此外，B.可以有效地根除对妥布霉素具有内在抗性的洋葱。两个实施例均表明PEG-PLGA颗粒在体外的改善或甚至恢复的功效。该项目旨在将第一个资助期内获得的体外结果转移到大鼠模型（慢性铜绿假单胞菌肺部感染模型）中，以研究吸入纳米粒包封妥布霉素的体内安全性和有效性。目的是（i）阐明包封的妥布霉素的改善/恢复的功效的潜在机制，ii）配制适用于吸入的微米颗粒和纳米颗粒，并确认药物的充分肺部存款，（iii）表征体内安全性特征，和（iv）提供吸入妥布霉素的上级功效的概念验证-与纯吸入妥布霉素相比，

During the first period, using systematic variations during the formulation process, we developed and optimized different micro- and nanoparticle formulations of polyester polymers in which different antibiotics with antipseudomonal activity were stably and efficiently encapsulated. The particles were extensively characterized regarding their physicochemical characteristics, and storage forms were developed. Using in vitro assays, we were able to demonstrate that non-encapsulated tobramycin exhibits no activity against biofilms of Pseudomonas aeruginosa and Burkholderia cepacia. By contrast, nanoparticle encapsulation restored the activity of tobramycin against these biofilms. The effectiveness of poly(D,L-lactide-co-glycolide)-poly[(D,L-lactide-co-glycolide)-co-polyethylene glycol] (PEG-PLGA)-encapsulated tobramycin against the biofilms was 1000-fold higher compared to that of the free drug or a blend of both components. The effective concentration of the encapsulated tobramycin was even lower than the concentrations measured during the tobramycin i.v. treatment. Moreover, the biofilms of B. cepacia, which is intrinsically resistant to tobramycin, could be efficiently eradicated. Both examples indicate an improved or even restored efficacy of the PEG-PLGA particles in vitro. The proposed project aims to transfer the in vitro results obtained during the first funding period to a rat model (chronic P. aeruginosa lung infection model) to investigate the safety and efficacy of the inhaled nanoparticle-encapsulated tobramycin in vivo. The aims are to (i) clarify the mechanism underlying the improved/restored efficacy of the encapsulated tobramycin, ii) formulate micro- and nanoparticles that are applicable for inhalation and confirm a sufficient pulmonary deposit of the drug, (iii) characterize the safety profile in vivo, and (iv) provide proof-of-concept of the superior efficacy of the inhaled tobramycin-encapsulated formulation compared to that of purely inhaled tobramycin.