Combined Docetaxel-Loaded Perfluorocarbon Nanodroplets with Ultrasound-Mediated Blood-Brain Barrier Disruption for...

Glioblastoma (GBM) remains the most aggressive primary brain tumor, characterized by a high recurrence rate and a poor prognosis, particularly due to the blood-brain/tumor barrier, which severely limits the intracerebral drug delivery. This study evaluates a novel strategy combining a nanomedicine-based drug delivery approach with focused ultrasound-mediated blood-brain barrier disruption (FUS-BBBD) to achieve localized therapeutic drug concentrations to the tumor.

Paclitaxel and docetaxel were encapsulated in perfluorooctyl bromide nanodroplets, stabilized with fluorinated surfactants. The formulation was optimized and characterized in terms of drug loading, encapsulation efficiency, size, size distribution and stability. In vivo pharmacokinetics (PK) and safety were assessed in C57BL/6 mice. Therapeutic efficacy was evaluated using an orthotopic syngeneic GL261 glioma model combined with hemispheric 1.5 MHz FUS-BBBD.

Docetaxel-loaded nanodroplets (DTX-NDs) emerge as the most promising candidates. Optimized DTX-NDs exhibited a mean diameter of 62 ± 4 nm with an encapsulation efficiency exceeding 90%, a good stability achieved by freeze-drying, and a sustained release profile. PK analysis demonstrated a 28-fold reduction in systemic clearance and a significantly prolonged terminal half-life compared to free docetaxel. Quantitative LC-MS confirmed that FUS-BBBD enhanced docetaxel accumulation 9-fold in healthy brain tissue (p < 0.05) and 6-fold in GL261 glioma-bearing mice (p < 0.05) when using the nanodroplet formulation. An optimized treatment plan with DTX-NDs (20 mg kg^-1 every 72 hours) successfully balanced efficacy and safety, extending median survival to 36 days versus 20 days for free DTX (p < 0.05), while achieving a 33% long-term survival rate. Toxicity was limited to transient and reversible hepatotoxicity.

This study demonstrates that the repeated combination of DTX-NDs and FUS-BBBD is a biocompatible and effective strategy for enhancing brain drug delivery while minimizing peripheral toxicity, thereby offering a promising translational approach for the treatment of GBM.