Overcoming the barriers in micellar drug delivery: loading efficiency, in vivo stability, and micelle-cell interaction

Importance of the field. Spontaneously constructed from block copolymers in aqueous media, the polymer micelle has been extensively studied as a potential carrier of poorly water-soluble drugs, but cellular uptake pathways and stability of micelles in blood have not yet been clearly understood. An in-depth insight into the physical and biological behaviors of polymer micelles is necessitated for designing next-generation micelles. Areas covered in this review: This review suggests possible solutions to improve micellar drug loading capacity, scrutinizes the parameters influencing the micelle stability in blood, and also discusses the fate of micelles in cellular and in vivo environment, respectively. Direct and indirect evidences from the literatures mostly published after 90's were collected, analyzed and summarized. What the reader will gain: A critical analysis of micelle's stability in vivo and micelle-cell interaction is provided to highlight the key issues to be addressed to affirm that micelle can properly work as a drug carrier in clinical settings. Take home message: With a clear understanding of its behaviors in biological environment, the polymer micelle is a promising nanocarrier for chemotherapy.