Smart oral delivery of curcumin nanoparticulate systems for targeted colorectal cancer therapy: strategies, applications, and future perspectives

Colorectal cancer (CRC) offers a unique opportunity for oral nanomedicine due to its anatomical location and distinct physiological gradients. Curcumin (CUR) demonstrates immense therapeutic potential against CRC but is limited by poor solubility, rapid metabolism, and low bioavailability. While conventional nanoparticulate systems have been explored, the field is now transitioning toward intelligent, stimuli-responsive targeting. This "smart drug delivery" leverages CRC's pathophysiological hallmarks, including pH gradients, dysregulated enzymes, redox imbalance, and receptor upregulation to inform nanomedicine design. These systems transcend passive transport by operating through a cascading logic of microenvironment sensing, signal-responsive activation, and precision release, enabling spatiotemporally controlled drug release specifically within colorectal tumors via endogenous signals or external triggers. This review critically analyzes this paradigm shift. We briefly outline CUR's multifaceted pharmacological profile against CRC before providing a comprehensive overview of smart responsive oral CUR nanoformulations, categorized by their activation mechanisms. We particularly emphasize the emerging trend of combined targeting strategies, where multiple mechanisms are integrated to achieve synergistic precision and enhanced therapeutic outcomes. Finally, we offer a forward-looking perspective on challenges and future directions, underscoring the importance of patient stratification, advanced biomimetic designs, and clinical translation of these sophisticated systems. Search: PubMed, SciFinder, Google Scholar, through January 2026.