Vesicle-based formulations for pain treatment: a narrative review

Pain, a complex and debilitating condition, necessitates innovative therapeutic strategies to alleviate suffering and enhance patients' quality of life. Vesicular systems hold the potential to enhance precision of drug localisation and release, prolong the duration of therapeutic action and mitigate adverse events associated with long-term pharmacotherapy. This review critically assesses the current state-of-the-art in vesicle-based formulations (liposomes, polymersomes, ethosomes, and niosomes) for pain management applications. We highlight formulation engineering strategies used to optimise drug pharmacokinetics, present preclinical findings of experimental delivery systems, and discuss the clinical evidence for the benefits of clinically approved formulations. We present the challenges and outlook for future improvements in long-acting anaesthetic and analgesic formulation development.