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，持续的局部阴道递送可能会大大提高杀微生物剂的保护功效和用户可接受性，目前正在开发用于预防艾滋病和其他性传播疾病的杀微生物剂。现在用于粘膜给药的纳米颗粒是亲粘膜的，并且与黏液凝胶紧密结合。不幸的是，这些传统的纳米颗粒会被腔内粘液迅速清除，很少能到达上皮表面；腔内粘液在几分钟到几小时内被清除。我们的第一个假设是，快速穿透粘液的非亲粘液颗粒通过扩散通过腔内粘液到达粘附在上皮上的未搅拌的粘液层，从而提供更长，更有效，持续的递送。我们的第二个假设是，被细胞粘附分子修饰的穿透黏液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，这是一个比清除黏液分泌物慢得多的过程。病毒进化出了穿透黏液分泌物并与目标上皮细胞结合的机制，并且，以病毒颗粒为导向，我们最近开发出了能够快速扩散通过人类黏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黏液穿透性和细胞粘附性颗粒是否比传统的亲黏液纳米颗粒更有效、更长久地留在阴道内。在Aim 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穿透黏液和常规纳米颗粒的扩散运输速率。在实验2中，我们将测定实验1中纳米颗粒在小鼠体内的滞留时间和阴道分布。颗粒将被荧光标记，上皮分布的细节将用组织学方法检查。阴道滞留时间将在活体动物中使用全身荧光成像进行量化。在Aim 3中，我们将使用一种新的可生物降解聚合物平台合成穿透黏液的细胞粘附颗粒。我们预计常规的嗜粘颗粒将在数小时内被清除，但粘液穿透颗粒，特别是细胞粘附的粘液穿透颗粒，将完全覆盖上皮并保留数天。

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.