Science has been trying to deal with complex diseases, like cancer, for a long time. Indeed, the side effects of the conventional treatment methods are tremendous, in some cases irreversible. This kind of problems demands a solution. Therefore, novel drug delivery systems are devised to mitigate the negative impacts of conventional ones. Polymeric nanocarrier systems are of great importance in this newly opened field. Polymers having been vastly investigated are common in some properties, such as their being biocompatibility and biodegradability. Generally speaking, a set of properties is required to achieve optimum delivery of drugs to target organs with minimum side effects. To do so, some measures should be taken. First of all, the strategy for release should be determined, categorized into two main branches, active and passive. Next, the drug release method should be engineered. Generally, there are two main categories for drug release, exogenous and endogenous. In this review, some of the chief subcategories of any aforementioned items are discussed. In the end, we catch up on already engineered nanocarriers' administration to the human body, possible toxic effects, if any, and the routes for affecting as a toxin.

中文翻译：

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高分子药物纳米载体的靶向递送，药物释放策略和毒性研究

长期以来，科学一直在努力应对复杂的疾病，例如癌症。确实，常规治疗方法的副作用是巨大的，在某些情况下是不可逆的。这种问题需要解决方案。因此，设计了新颖的药物输送系统以减轻常规药物输送系统的负面影响。聚合物纳米载体系统在这个新开放的领域中非常重要。已被广泛研究的聚合物在某些性质上是常见的，例如它们的生物相容性和生物降解性。一般而言，需要一组特性才能以最小的副作用实现药物向靶器官的最佳递送。为此，应采取一些措施。首先，应该确定释放策略，将其分为主动和被动两个主要分支。下一个，应设计药物释放方法。通常，药物释放有两个主要类别，外源性和内源性。在这篇评论中，讨论了任何前述项目的一些主要子类别。最后，我们了解了已经设计的纳米载体对人体的给药，可能的毒性作用（如果有的话）以及影响作为毒素的途径。