An Inhaled Clofazimine Formulation for the Treatment of Tuberculosis

项目摘要 据世界卫生组织统计，世界上约有三分之一的人口感染了 结核分枝杆菌（Mtb），多达10%的感染者会发展为活动性结核病 (TB)在感染后的某个时候。结核病是一种可治愈的疾病，但其死亡率仍然很高（2016年为1.7 100万人死于该病）。由于结核病发病率高，全球结核病控制工作十分复杂 以及耐药结核病的出现。Cfz是一种最近被添加到 世卫组织推荐的药物清单用于治疗耐药结核菌株，能够有效缩短治疗时间。 然而，Cfz的口服给药带来了诸如延迟起效和有害副作用的问题 （胃肠道、皮肤、心脏）。改善结核病治疗的现有目标包括开发有效的 药物的雾化递送，例如Cfz，以直接靶向肺部。改进药物的开发 治疗疾病的药物已被列为国家研究所战略计划的优先事项， 过敏和传染病（NIAID）。已经研究了微粒包封用于气雾剂递送， 结核病药物。在开发有效的颗粒递送系统中的关键参数是：1）肺深部 递送，2）肺泡巨噬细胞的颗粒摄取（Mtb侵袭和复制的主要部位）3） 药物释放，4）药物剂量和5）安全性。平衡递送的药物质量与释放以及 确保有效的分散和安全性对于有效的制剂是至关重要的。精确控制的微粒 可以使用喷雾干燥制备用于肺深部递送和大小介导的吞噬作用的超粒度。 为了解决药物释放和剂量的限制，Lynntech建议开发聚合缩醛 包封Cfz的葡聚糖（Ac-Dex）。差异药物释放可以通过使用pH- 反应性Ac-Dex颗粒，能够在吞噬溶酶体的酸性环境中快速释放Cfz 在大部分Mtb感染发生的地方增加。这种释放机制可以快速地使Cfz的MIC能够被释放。 在巨噬细胞内达到，同时增加有效性，同时减少所需的剂量 Cfz，从而减少副作用。此外，Ac-Dex降解的副产物（乙醇、丙酮、葡聚糖） 是相对良性的。我们的具体目标是提供使用和调整这些AC的概念验证， 用于在Mtb感染的细胞内释放活性Cfz的Dex颗粒。这些目标包括：（1）开发新的Ac-Dex 包封Cfz的颗粒，（2）证明颗粒摄取和释放增强体外Cfz递送， 杀菌作用，和（3）在药代动力学（PK）和体内功效研究中评估摄取和释放。 第一阶段的成功完成将证明开发用于吸入的Ac-Dex颗粒的可行性 Cfz的交付。然后，我们将把最佳样品加入干粉制剂中，用于在 未来的第二阶段工作。这项研究最终形成了一个平台，用于提供各种结核病药物， 其组合用于TB治疗。

PROJECT SUMMARY According to the World Health Organization, about one third of the world’s population is infected with Mycobacterium tuberculosis (Mtb), and as many as 10% of infected individuals will develop active tuberculosis (TB) at some point after infection. TB is a curable disease, yet it still has a high mortality rate (in 2016, 1.7 million people died from the disease). The global control of TB is complicated due to the high incidence of TB in developing countries, and the emergence of drug resistant TB. Cfz is a drug that has been recently added to WHO recommended list of drugs to treat drug resistant TB strains, effectively able to shorten treatment times. However, oral administration of Cfz poses problems such as delayed onset and deleterious side effects (gastrointestinal, dermal, cardiac). An existing goal to improve TB treatment consists of developing effective aerosolized delivery of drugs, such as Cfz, to directly target the lungs. The development of improved drug therapeutics for treatment of diseases has been listed as a priority in the strategic plan of the National Institute of Allergy and Infectious Diseases (NIAID). Microparticle encapsulation has been studied for aerosol delivery of TB drugs. Critical parameters in the development of an efficient particle delivery system are: 1) deep lung delivery, 2) particle uptake by alveolar macrophages (the primary site of invasion and replication of Mtb) 3) drug release, 4) drug dosage, and 5) safety. Balancing the mass of drug delivered against release as well as ensuring efficient dispersal and safety is critical to an effective formulation. Microparticles with precise control over particle size for deep lung delivery and size-mediated phagocytosis can be prepared using spray drying. To address the limitations in drug release and dosage, Lynntech proposes to develop polymeric acetalated dextran (Ac-Dex) encapsulating Cfz. Differential drug release can be achieved through the use of pH- responsive Ac-Dex particles, able to release Cfz within the acidic environment in phagolysosomes, quickly increasing where the bulk of Mtb infection occurs. This release mechanism can quickly enable MIC of Cfz to be reached within macrophages, simultaneously increasing effectiveness while reducing the required dosage of Cfz, thus reducing side effects. Additionally, the by-products of Ac-Dex degradation (ethanol, acetone, dextran) are relatively benign. Our specific aims are devised to provide proof-of-concept on using and tuning these Ac- Dex particles for active Cfz release within Mtb infected cells. These aims include (1) developing novel Ac-Dex particles encapsulating Cfz, (2) demonstrate that particle uptake and release enhances in vitro Cfz delivery and bactericidal effect, and (3) evaluate uptake and release in pharmacokinetic (PK) and efficacy in vivo studies. The successful completion Phase I will demonstrate feasibility of developing Ac-Dex particles for inhaled delivery of Cfz. We will then incorporate optimal samples into dry powder formulations for aerosol delivery in a future Phase II effort. This research ultimately forms a platform for delivery of a variety of TB drugs and combinations thereof for TB treatment.