Background: Despite advances in surgery, radiotherapy and chemotherapy, brain tumors
are still a major health issue due to poor prognosis and high mortality rate. The current treatment
options have limited efficiency. The main barriers to effective clinical treatment are systemic
toxicity of cytotoxic compounds, the physical and functional barrier of the blood-brain barrier (BBB),
and low selectivity of the therapeutic agents to tumor cells.
Objective: The study aimed to review the advances in targeted drug delivery systems and strategies
for brain tumors.
Methods: We searched the electronic databases of PubMed, EMBASE, Web of Science, BIOSIS
Previews, Cambridge Scientific Abstracts, google scholar and additional sources for published and
unpublished trials using the set search terms. The date of the most recent search was 20 March
2020. The studies investigating the applications of targeted drug delivery for brain tumors were collected
and the most relevant studies were selected for a comprehensive review.
Results: Different anticancer agents and nucleic acid-based therapies have been developed and assessed
as novel targeted drug delivery techniques for brain tumors. New vehicles include polymeric
and liposomal nanoparticles (NPs), wafers, microchips, microparticle-based nanosystems and
cells-based vectors. Strong evidence from preclinical and translational studies indicate the great potential
of these NPs-based technologies for use in brain tumors and improving the therapeutic outcomes.
Research is ongoing to develop effective new anticancer agents as well as strategies for
BBB modulation and penetration.
Conclusion: New targeted drug delivery systems based on stimuli-responsive NPs have shown
promising outcomes in brain tumors. Advances in material design and nanochemistry lead to enhanced
intracranial concentrations. Non-invasive technologies such as magnetic resonance imaging-
guided ultrasound and high-intensity focused ultrasound have been utilized for BBB modulation
with higher precision and improved drug delivery performance.