Plant-derived extracellular vesicles for itraconazole delivery across the blood-brain barrier for potential glioblastoma treatment.

Background A major challenge in central nervous system disorders such glioblastoma includes the presence of a blood-brain barrier which restricts the delivery of therapeutic agents to the brain, thereby limiting the effectiveness of most conventional treatments. Moreover, the discovery of novel drugs for glioblastoma has been limited hence drug repurposing has gained traction leveraging existing drugs like itraconazole. Plant-derived extracellular vesicles (PDEVs) have potential as a natural pharmaceutical delivery system owing to their therapeutic capabilities. These PDEVs may be a good candidate for blood-brain barrier permeation due to their biomolecular composition and high drug loading efficiency of itraconazole. In this work, PDEVs isolated from aloe aborescens (aloe), Zingiber officinale (ginger) and Nigella sativa seeds [black cumin seeds (BCS)] were compared in terms of their physicochemical properties, drug release kinetics, cytotoxicity, cellular uptake in glioblastoma cells and BBB permeability. Results All PDEVs displayed nanoscale sizes ranging from 103.5 to 141 nm with negative surface charge and a spherical morphological shape observed via SEM. The drug release kinetics was assessed using different mathematical models depicting the PDEVs prolonged drug release with < 50% releasing over 21 days. The cytotoxicity studies showed that the PDEVs resulted in a higher cell viability in the non-cancerous cell line compared to A172 glioblastoma cell line. The cellular internalization of the drug showed poor uptake of blank PDEVs compared to loaded PDEVs in glioblastoma cells. The BBB permeability test showed that ginger and aloe EVs permeated the BBB whilst BCS blank and loaded EVs did not permeate the BBB. Conclusions This delivery system improves the ability of plant-derived extracellular vesicles to cross the blood-brain barrier, addressing a key challenge in delivering treatments to the brain. Through successful encapsulation of itraconazole, it paves the way for glioblastoma treatment by repurposing itraconazole with improved efficacy and reduced side effects. Furthermore, this can be incorporated in various drug delivery vehicles depending on the route of administration and therapeutic outcome i.e. intranasal, intravenous, or oral route. Future studies focus on determining the composition of PDEVs to enable engineering strategies for next generation targeting via surface modification.