Purpose: Glioblastoma multiforme (GBM) has a poor prognosis due to limited drug delivery across the blood–brain barrier (BBB), therapeutic resistance, and recurrence. Nanocarriers may improve temozolomide (TMZ) delivery, but it is unclear which nanocarrier type—polymeric nanoparticles (PNPs), solid lipid nanoparticles (SLNs), or nanostructured lipid carriers (NLCs)—is optimal for glioblastoma chemotherapy.
Hypothesis: If TMZ is loaded into PNPs, SLNs, and NLCs, then the nanocarrier with the most favourable physicochemical properties—particularly NLCs due to their imperfect lipid crystal structure and higher drug loading—will achieve the greatest anti-tumour efficacy in U87MG glioma cells and in glioma-bearing mice.
Aims: Prepare TMZ-loaded PNPs (T-PNPs), SLNs (T-SLNs), and NLCs (T-NLCs). - Characterise particle size, zeta potential, encapsulation efficiency, drug loading, serum stability, and in vitro release. - Compare in vitro cytotoxicity against U87MG malignant glioma cells. - Compare in vivo anti-tumour efficacy in mice bearing U87MG tumours and identify the best carrier for glioblastoma chemotherapy.
Delivery system:
Component: Matrix; T-PNPs: PLGA (50:50); T-SLNs: Stearic acid + injectable soya lecithin; T-NLCs: COMPRITOL® 888 ATO + Cremophor ELP + soybean phosphatidylcholine + soya lecithin
Component: Stabiliser/surfactant; T-PNPs: 1% PVA; T-SLNs: 1% DDAB; T-NLCs: Tween-80 + 0.5% DDAB
Component: Payload; T-PNPs: Temozolomide (TMZ); T-SLNs: TMZ; T-NLCs: TMZ
Component: Targeting ligand; T-PNPs: None; T-SLNs: None; T-NLCs: None
Component: Size; T-PNPs: 109.1 ± 4.3 nm; T-SLNs: 94.6 ± 3.1 nm; T-NLCs: 121.4 ± 5.6 nm
Component: Zeta potential; T-PNPs: −28.2 ± 3.1 mV; T-SLNs: +41.2 ± 4.1 mV; T-NLCs: +29.1 ± 2.4 mV
Component: EE; T-PNPs: 83.6 ± 3.2%; T-SLNs: 82.3 ± 2.8%; T-NLCs: 81.4 ± 3.7%
Component: DL; T-PNPs: 10.8 ± 1.1%; T-SLNs: 9.6 ± 0.9%; T-NLCs: 5.2 ± 0.6%
Approach: In vitro: U87MG human malignant glioma cells; MTT assay at TMZ concentrations 0.1–10 µM for 48 h. - In vivo: BALB/c nude mice bearing subcutaneous U87MG tumours; eight groups (n = 6/group): saline control, blank PNPs, blank SLNs, blank NLCs, T-SOL, T-PNPs, T-SLNs, T-NLCs. - Dosing: Intravenous tail-vein injection every 3 days for 21 days. - Disease context: Glioblastoma/glioma chemotherapy. - No orthotopic brain tumour model and no direct BBB crossing assessment.
Key methods: Physicochemical characterisation: TEM, dynamic light scattering (size, PDI, zeta potential), ICP-MS for EE/DL. - Serum stability: Incubation in 50% FBS for 24 h; size and EE monitored. - In vitro release: Dialysis method in PBS (pH 7.4). - Cytotoxicity: MTT assay; IC50 calculation. - In vivo efficacy: Tumour volume measured every 3 days; tumour inhibition rate calculated from tumour weight.
Key results: Particle properties: All formulations were ~95–121 nm, spherical. T-PNPs were anionic; T-SLNs and T-NLCs were cationic. EE >80% for all; DL highest for T-PNPs (10.8%) and lowest for T-NLCs (5.2%). - Serum stability: All three carriers were stable in 50% FBS for 24 h with no significant size or EE changes. - In vitro cytotoxicity (IC50): T-SOL = 9.12 µM; T-PNPs = 4.86 µM; T-SLNs = 2.93 µM; T-NLCs = 0.78 µM. T-NLCs were ~4× and ~7× more potent than T-SLNs and T-PNPs, respectively. - In vivo anti-tumour efficacy (day 21 tumour volume): Control = 1192 mm³; T-PNPs = 656 mm³; T-SLNs = 487 mm³; T-NLCs = 183 mm³. Tumour inhibition rates: T-NLCs = 85%, T-SLNs = 59%, T-PNPs = 45%, T-SOL = 27%.
Interpretation: The authors claim that NLCs are the best of the three nanocarriers for TMZ delivery in glioblastoma chemotherapy. T-NLCs more efficiently delivered TMZ to U87MG cells and produced greater in vitro cytotoxicity and in vivo tumour inhibition than T-SLNs and T-PNPs. They conclude that T-NLCs could be an excellent drug delivery system for glioblastoma chemotherapy.
Limitations: Subcutaneous tumour model only: No orthotopic brain tumour model; BBB penetration was not directly evaluated. - No survival data: Tumour volume and inhibition rate only; no median survival or long-term follow-up. - No toxicity/biodistribution: Systemic toxicity, organ distribution, and clearance were not reported. - No targeting ligand: Delivery relies on passive accumulation; no active glioma targeting. - Single cell line: U87MG only. - No comparison with clinically used TMZ formulation beyond free TMZ solution. - Short therapeutic period: 21 days; long-term efficacy and recurrence not assessed. - No mechanistic uptake studies: Why NLCs perform better is inferred from physicochemical properties, not directly demonstrated.
