Mucus Penetrating Nanoparticles for Vaginal Drug Delivery

描述（由申请人提供）：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会大大改善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功效和用户可接受性。现在用于粘膜药物递送的纳米颗粒是亲粘液的，并且与粘液凝胶紧密结合。不幸的是，这些常规的纳米颗粒被管腔粘液快速清除，并且很少到达上皮表面;管腔粘液在几分钟至几小时内被清除。我们的第一个假设是，快速穿透粘液的非嗜粘液颗粒将通过扩散穿过管腔粘液到达粘附于上皮的未搅拌的粘液层来提供更长且更有效的持续递送。我们的第二个假设是，用细胞粘附分子修饰的粘液穿透颗粒将以高效率到达并结合上皮细胞，并将持续存在直到上皮细胞脱落，这是一个比粘液分泌物清除慢得多的过程。病毒进化出了穿透粘液分泌物并与靶上皮细胞结合的机制，并且，使用病毒颗粒作为向导，我们最近开发出了可以通过人类粘液分泌物快速扩散并与上皮细胞紧密结合的纳米颗粒。我们将在小鼠中测试我们的粘液渗透和细胞粘附颗粒是否比传统的嗜粘液纳米颗粒更有效地保留在阴道中更长时间。在目标1中，我们将充分表征颗粒大小和表面性质，并使用颗粒跟踪来观察未稀释的人宫颈阴道粘液中的粘液渗透性和常规纳米颗粒的扩散转运速率。在目标2中，我们将在小鼠中确定目标1中表征的纳米颗粒的保留时间和阴道分布。将对颗粒进行荧光标记，并采用组织学方法检查上皮分布的详细信息。将使用全身荧光成像对活体动物的阴道滞留时间进行定量。在目标3中，我们将使用新的可生物降解的聚合物平台合成粘液穿透的细胞粘附颗粒。我们预计传统的嗜粘液颗粒将在数小时内被清除，但粘液穿透性颗粒，特别是细胞粘附的粘液穿透性颗粒，将实现完全的上皮覆盖并保留数天。 公共卫生相关性：如果能够开发出持续阴道分娩的方法，目前正在开发的用于预防艾滋病和其他性传播疾病的阴道杀微生物剂以及用于多种阴道感染的药物疗法可能会大大加强。药物的局部应用通常减少大多数类型的副作用，但局部应用通常具有相对较短的作用或保护持续时间：阴道杀精剂仅有效约1小时。最近，我们发现了生产粘液穿透纳米颗粒的方法，这些方法可能为持续局部递送药物和杀微生物剂到阴道上皮提供有效方法。该申请寻求资金以在动物中测试以下假设：粘液穿透纳米颗粒将比常规药物递送纳米颗粒在阴道内保留显著更长的时间，因为常规纳米颗粒强烈粘附于粘液，因此在粘液脱落时（通常数分钟至数小时）被迅速清除。此外，似乎有可能发展粘液穿透颗粒，这些颗粒可以扩散到阴道上皮细胞并与之结合。这样的颗粒可能提供持续数天的局部药物递送。如果成功的话，这个项目可能会导致持续药物输送系统的开发，这种系统比现在可用的方法更方便，更有效地预防和治疗疾病。

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.