Nanocarriers as Drug Delivery System for Chemotherapeutic Agents: from Inception to Clinical Implementation

This review investigates the advancements of nanocarrier-based chemotherapeutic agents from their inception to present-day implementation. It focuses on the types of nanocarriers introduced to date, the FDA-approved nanomedicines and the nanomedicines undergoing clinical trials, and particularly discusses how nanomedicine overcomes many biochemical, biophysical, and biomedical barriers whose efficacy far exceeds other conventional drug delivery systems (DDS). This review highlights the unique ability of nanocarriers that improve the solubility of drugs, effectively transporting and accumulating large drug doses specifically to tumour cells, destroying them, and exploiting the erratic tumour microenvironment (TME) due to defective angiogenesis by cancer cells, setting nanocarriers apart from conventional DDS. Nanomedicines like Doxil rely on passive targeting and are effective only in solid tumours, displaying the Enhanced Permeability and Retention (EPR) effect. Therefore, different approaches are taken to improve the EPR effect in metastatic cancer through active targeting. Nanomedicine circumvents efflux transporters and reduces multi-drug resistance. Aside from being used as a medium for anti-cancer agents, nanocarriers can also be used for cancer immunotherapy, gene therapy, and diagnostic purposes. Nanomedicines enhance drug delivery, reduce toxicity, and improve the therapeutic efficacy in cancer therapy. Nanomedicine also aids in cancer imaging and enables advanced immunotherapy and gene therapy. These innovations can lead to more effective, personalized cancer treatments with fewer side effects. However, nanocarriers still has some limitations and challenges such as its own toxicity, payload issues and immunogenic reactions, which are further needed to be improved.