Improving the Treatment of Brain Gliomas Through Small-Particle-Size Paclitaxel-Loaded Micelles with a High Safety Profile

Background/Objectives: Paclitaxel (PTX) is widely used in the treatment of a variety of solid tumours due to its broad-spectrum anti-tumour activity, but its use in brain gliomas is limited by insufficient blood–brain tumour barrier (BBTB) penetration and systemic toxicity. The aim of this study was to develop a Solutol HS-15-based micellar nanoparticle (PSM) to enhance the brain glioma targeting of PTX and reduce toxicity. Methods: PSMs were prepared by solvent injection and characterised for particle size, encapsulation rate, haemolysis rate and in vitro release properties. A C6 in situ glioma mouse model was used to assess the brain targeting and anti-tumour effects of the PSM by in vivo imaging, tissue homogenate fluorescence analysis and bioluminescence monitoring. Meanwhile, its safety was evaluated by weight monitoring, serum biochemical indexes and histopathological analysis. Results: The particle size of PSMs was 13.45 ± 0.70 nm, with an encapsulation rate of 96.39%, and it demonstrated excellent cellular uptake. In tumour-bearing mice, PSMs significantly enhanced brain tumour targeting with a brain drug concentration 5.94 times higher than that of free PTX. Compared with Taxol, PSMs significantly inhibited tumour growth (terminal luminescence intensity <1 × 10⁶ p/s/cm²/Sr) and did not cause significant liver or kidney toxicity or body weight loss. Conclusions: PSMs achieve an efficient accumulation of brain gliomas through passive targeting and EPR effects while significantly reducing the systemic toxicity of PTX. Its simple preparation process and excellent therapeutic efficacy support its use as a potential clinically translational candidate for glioma treatment.