Mucus Penetrating Nanoparticles for Vaginal Drug Delivery

描述(申请人提供)：纳米颗粒的持续药物释放可以通过减少全身副作用来改善粘膜治疗，持续的局部阴道给药可能极大地提高目前正在开发的用于预防艾滋病和其他性传播疾病的杀微生物剂的保护效果和用户可接受性。现在用于粘膜给药的纳米颗粒是亲粘性的，与粘液凝胶紧密结合。不幸的是，这些传统的纳米颗粒很快就会被管腔粘液清除，很少能到达上皮表面；管腔粘液在几分钟到几小时内就能清除。我们的第一个假设是，快速穿透粘液的非亲粘性颗粒将通过腔粘液扩散到附着在上皮上的未搅拌的粘液层，从而提供更长时间和更有效的持续输送。我们的第二个假设是，带有细胞黏附分子装饰的黏液穿透颗粒将以高效率到达并结合到上皮细胞，并将持续存在，直到上皮细胞脱落，这一过程比清除黏液分泌物慢得多。病毒进化出穿透粘液分泌物并结合到靶上皮细胞的机制，最近我们利用病毒颗粒作为向导，开发出了能够迅速扩散到人粘液分泌物并与上皮细胞紧密结合的纳米颗粒。我们将在小鼠身上测试我们的粘液穿透性和细胞粘附性颗粒是否比传统的亲粘性纳米颗粒更有效地在阴道中保留更长时间。在目标1中，我们将充分表征颗粒的大小和表面性质，并使用颗粒跟踪来观察粘液穿透性纳米颗粒和常规纳米颗粒在未稀释的人宫颈阴道粘液中的扩散传输速率。在目标2中，我们将测定在目标1中表征的纳米颗粒在小鼠体内的保留时间和阴道分布。这些颗粒将被荧光标记，并将用组织学方法检查上皮分布的细节。活体动物的阴道滞留时间将使用全身荧光成像进行量化。在目标3中，我们将使用一种新的可生物降解的聚合物平台来合成粘液穿透、细胞黏附的颗粒。我们预计传统的亲粘性颗粒将在几个小时内清除，但渗透粘液的颗粒，特别是贴壁细胞的渗透粘液颗粒，将实现完全的上皮覆盖并保留数天。 公共卫生相关性：目前正在开发用于预防艾滋病和其他性传播疾病的阴道杀菌剂，如果能够开发出持续阴道分娩的方法，许多类型的阴道感染的药物治疗可能会得到极大的加强。局部用药通常会减少大多数类型的副作用，但局部用药的作用或保护持续时间通常相对较短：阴道杀精剂仅有效约1小时。最近，我们发现了制造粘液穿透纳米颗粒的方法，这可能为药物和杀菌剂持续局部输送到阴道上皮提供一种有效的方法。这项申请寻求资金在动物身上测试这一假设，即穿透粘液的纳米颗粒将在阴道内保留的时间比传统的药物输送纳米颗粒要长得多，因为传统的纳米颗粒强烈地附着在粘液上，因此在粘液排出时就会被迅速清除(通常是几分钟到几小时)。此外，似乎有可能形成能够穿透粘液的颗粒，这种颗粒可以扩散到阴道内的上皮细胞，并与其结合。这种颗粒很可能提供持续几天的局部药物输送。如果成功，该项目可能导致开发出比现有方法更方便、更有效地预防和治疗疾病的持续给药系统。

DESCRIPTION (provided by applicant): Sustained drug release from nanoparticles can improve mucosal therapies by reducing systemic side-effects, and sustained topical vaginal delivery is likely to greatly improve protective efficacy, and user-acceptability, of microbicides now being developed for protection against AIDS and other sexually transmitted diseases. Nanoparticles now used for mucosal drug delivery are mucophilic and bind tightly to mucus gels. Unfortunately, these conventional nanoparticles are rapidly cleared with luminal mucus and very few reach the epithelial surface; luminal mucus is cleared within minutes to hours. Our first hypothesis is that non-mucophilic particles that rapidly penetrate mucus will provide longer, and more efficient, sustained delivery, by diffusing through luminal mucus to reach the unstirred layer of mucus that adheres to the epithelium. Our second hypothesis is that mucus-penetrating particles decorated with cell-adhesion molecules will reach and bind to epithelial cells with high efficiency, and will persist in place until the epithelial cells are shed, a much slower process than clearance of mucus secretions. Viruses evolved mechanisms to penetrate mucus secretions and bind to target epithelial cells, and, using virus particles as guides, we have recently developed nanoparticles that can rapidly diffuse through human mucus secretions and bind tightly to epithelial cells. We will test in mice whether our mucus-penetrating, and cell-adherent, particles are retained more efficiently and for longer times in the vagina than conventional mucophilic nanoparticles. In Aim 1, we will fully characterize particle size and surface properties, and use particle tracking to observe diffusional transport rates of mucus-penetrating and conventional nanoparticles in undiluted human cervico-vaginal mucus. In Aim 2, we will determine in mice the retention times and vaginal distributions of the nanoparticles characterized in Aim 1. The particles will be fluorescently labeled, and details of epithelial distribution will be examined with histologic methods. Vaginal retention times will be quantified in living animals using whole-body fluorescence imaging. In Aim 3, we will synthesize mucus-penetrating, cell-adherent particles using a new biodegradable polymer platform. We expect conventional mucophilic particles will be cleared within hours, but mucus-penetrating, and especially cell-adherent mucus-penetrating particles, will achieve complete epithelial coverage and be retained for days. Public Health Relevance: Vaginal microbicides now being developed to prevent AIDS and other sexually transmitted diseases, and drug therapies for many types of vaginal infections are likely to be greatly enhanced if methods can be developed for sustained vaginal delivery. Topical applications of drugs typically reduces most types of side effects, but topical applications typically have relatively short durations of action or protection: Vaginal spermicidal are effective for only about 1 hour. Recently we discovered ways to produce mucus-penetrating nanoparticles that are likely to provide an efficient method for sustained topical delivery of drugs and microbicides to the vaginal epithelium. This application seeks funds to test in animals the hypothesis that mucus-penetrating nanoparticles will be retained within the vagina for significantly longer times than conventional drug-delivery nanoparticles since conventional nanoparticles adhere strongly to mucus and hence are cleared as rapidly as the mucus is shed (typically minutes to hours). In addition, it appears possible to develop mucus-penetrating particles than can diffuse to, and bind to, the epithelial cells that line the vagina. Such particles are likely to provide sustained topical drug delivery for several days. If successful, this project could lead to the development of sustained drug delivery systems that are more convenient, and more effective, for preventing and treating diseases than methods now available.