Breast cancer (BC) is a highly diagnosed and topmost cause of death in females worldwide. Drug repurposing (DR) has shown great potential against BC by overcoming major shortcomings of approved anticancer therapeutics. However, poor physicochemical properties, pharmacokinetic performance, stability, non-selectivity to tumors, and side effects are severe hurdles in repurposed drug delivery against BC. The variety of nanocarriers (NCs) has shown great promise in delivering repurposed therapeutics for effective treatment of BC via improving solubility, stability, tumor selectivity and reducing toxicity. Besides, delivering repurposed cargos via theranostic NCs can be helpful in the quick diagnosis and treatment of BC. Localized delivery of repurposed candidates through apt NCs can diminish the systemic side effects and improve anti-tumor effectiveness. However, breast tumor variability and tumor microenvironment have created several challenges to nanoparticulate delivery of repurposed cargos. This review focuses on DR as an ingenious strategy to treat BC and circumvent the drawbacks of approved anticancer therapeutics. Various nanoparticulate avenues delivering repurposed therapeutics, including non-oncology cargos and vaccines to target BC effectively, are discussed along with case studies. Moreover, clinical trial information on repurposed medications and vaccines for the treatment of BC is covered along with various obstacles in nanoparticulate drug delivery against cancer that have been so far identified. In a nutshell, DR and drug delivery of repurposed drugs via NCs appears to be a propitious approach in devastating BC.

乳腺癌 (BC) 是全球女性高度诊断和死亡的首要原因。通过克服已批准的抗癌疗法的主要缺点，药物再利用 (DR) 已显示出对抗 BC 的巨大潜力。然而，较差的物理化学性质、药代动力学性能、稳定性、对肿瘤的非选择性和副作用是针对 BC 重新利用药物递送的严重障碍。各种纳米载体 (NC) 在通过提高溶解度、稳定性、肿瘤选择性和降低毒性来提供可有效治疗 BC 的再利用疗法方面显示出巨大的前景。此外，通过治疗诊断 NC 有助于 BC 的快速诊断和治疗。通过 apt NC 对重新定位的候选者进行局部递送可以减少全身副作用并提高抗肿瘤效果。然而，乳腺肿瘤的变异性和肿瘤微环境给纳米颗粒输送重新利用的货物带来了一些挑战。本综述侧重于将 DR 作为一种巧妙的策略来治疗 BC 并规避已批准的抗癌疗法的缺点。与案例研究一起讨论了提供重新利用的治疗方法的各种纳米颗粒途径，包括有效靶向 BC 的非肿瘤货物和疫苗。而且，涵盖用于治疗 BC 的再利用药物和疫苗的临床试验信息以及迄今为止已确定的抗癌纳米颗粒药物递送的各种障碍。简而言之，重新利用药物的 DR 和药物输送通过NCs 似乎是毁灭性 BC 的一种有利方法。