Applications of micro/nano drug delivery systems in cancer pain management

Cancer pain, a critical complication associated with advanced malignant tumors, significantly diminishes patients' quality of life and complicates therapeutic management due to its multifactorial pathophysiology. Current clinical analgesics often face limitations such as tolerance, addiction, and dose-dependent systemic toxicity. In contrast, micro/nano drug delivery systems (MNDDs) have emerged as promising strategies for managing cancer pain, owing to their unique advantages in precise targeting, including tumor-selective and neuropathic pain pathway targeting, controlled release, and multi-modal synergistic therapeutic effects. This review comprehensively examines the pathophysiological mechanisms underlying cancer pain, critically analyzes the pharmacological constraints and clinical limitations of existing analgesic regimens, and summarizes recent advances in engineered MNDDs. Additionally, we discuss the translational potential of multifunctional MNDDs, offering a multidisciplinary perspective to advance the development of precision-engineered, toxicity-minimized analgesic interventions.