Nanocarrier with metal bridge for affinity based delivery of metal binding peptid

描述(申请人提供)：溶葡萄球菌酶是一种金属内肽酶，可溶解金黄色葡萄球菌，是治疗多重耐药金黄色葡萄球菌介导性感染的潜在系统疗法。然而，这种酶在体内的半衰期很短，到目前为止，它还没有成为一种全身治疗方法。我们的Pharmain公司建议应用一种新的药物传递纳米技术(药物纳米载体)，称为受保护的接枝共聚物(PGC)，与Pharmain的可逆结合(PRB)相结合，这是一种将含有金属结合位点的多肽和/或蛋白质可逆形成药物纳米载体的新技术。重要的是，纳米载体集中在血管通透性增加的部位，这使得能够在感染部位浓缩相关的药物。我们的长期目标是开发这种溶葡萄球菌酶的递送系统，考虑到它的锌结合结构域，似乎特别适合与我们的载体结合。设想的配方不仅能够延长酶的循环时间，还能在感染部位浓缩制剂，潜在地提高疗效，在整个治疗期间减少总剂量，并抑制耐药性的出现。在第一阶段项目中，我们提出了以下建议：目标1：设计、合成、提纯和表征含PRB的PGC。目的：用PGC/PRB制备溶葡萄球菌酶，并测定(I)PGC/pRb：溶葡萄球菌酶复合体的形成效率，(Ii)在有血清和无血清的情况下，溶葡萄球菌酶从PGC/pRb上的解离常数，(Iii)在咪唑和底物存在的情况下，体外释放载体上的溶葡萄球菌酶并保持其活性的能力。目的：比较PGC/PRB：溶葡萄球菌酶复合体和溶葡萄球菌酶复合体的体内药代动力学参数。第二阶段的研究将涉及对配制的溶葡萄球菌酶进行全面评估，包括葡萄球菌感染动物模型中的生物分布(在感染部位积累)和疗效。这些研究的目的是为设想的产品-溶葡萄球菌酶申请IND，在治疗侵袭性葡萄球菌感染的最佳感染部位定向递送系统中。 公共卫生相关性：对抗生素耐药金黄色葡萄球菌的现有治疗方法是有限的，大量高水平万古霉素耐药细菌的出现预示着，如果不开发新的治疗方法，公共卫生状况将非常严峻。这一阶段的申请旨在开发一种救命产品，用于侵袭性和系统性葡萄球菌感染引起的危及生命的紧急情况，最终目标是FDA提交IND申请。该产品将包含一种消化细菌细胞壁的酶(溶葡萄球菌酶)和一个纳米载体药物输送系统，该系统将使该酶稳定地清除患者血液和组织中的感染。

DESCRIPTION (provided by applicant): Lysostaphin, a metalloendopeptidase that is bacteriolytic for Staphylococcus aureus, is a potential systemic therapy for treating multidrug-resistant S. aureus mediated infections. However, the short half life of this enzyme in vivo has precluded its development thus far as a systemic therapy. Our company, PharmaIN proposes to apply a novel drug delivery nanotechnology (drug nanocarrier) called Protected Graft Copolymers (PGC) coupled with PharmaIN's Reversible Binding (PRB), a new technology for the reversible formulation of peptides and/or proteins containing a metal binding site to the drug nanocarrier. Importantly, the fact that the nanocarrier concentrates at sites of increased vascular permeability affords the ability to concentrate associated agents at the site of infection. Our long-term goal is to develop this delivery system for lysostaphin that, considering its Zn-binding domain, appears to be particularly well suited for association with our carrier. The envisioned formulation would not only offer the ability to prolong the circulation time of the enzyme but also concentrate the agent at sites of infection, potentially increasing efficacy, decreasing overall dose over the entire treatment period and suppressing the emergence of resistance. In the Phase I project, we propose the following: Aim 1: Design, synthesis, purification and characterization of PGC with PRB. Aim 2: Formulation of lysostaphin with PGC/PRB and determination of (i) formation efficiency of PGC/PRB:lysostaphin complex, (ii) dissociation constant of lysostaphin from the PGC/PRB in the presence and absence of serum, (iii) the ability, in vitro, to release lysostaphin from carrier in the presence of imidazole and substrate and maintain its activity without denaturation. Aim 3: Comparison of in vivo pharmacokinetic parameters of PGC/PRB:lysostaphin complex and lysostaphin. The Phase II studies will involve a comprehensive evaluation of formulated lysostaphin including biodistribution (accumulation at sites of infection) and efficacy in an animal model of staphylococcal infection. The studies are aimed toward filing an IND for the envisioned product - lysostaphin in an optimal infection site-directed delivery system for the treatment of invasive staphylococcal infections. Public Health Relevance: The available therapies for antibiotic resistant S. aureus bacteria are limited and the emergence of numerous high-level vancomycin resistant bacteria predicts a dire public health situation if new treatments aren't developed. This Phase I application is aimed toward developing a life-saving product for use in life threatening emergency caused by invasive and systemic staphylococcal infections with the eventual goal of FDA filing of an IND application. The product will contain an enzyme (lysostaphin) to digest bacterial cell walls and a nanocarrier drug delivery system that would make the enzyme stable to clear infections in blood and tissue of the patients.