Formulation and Optimization of Quercetin-Loaded PEGylated Multi-Walled Carbon Nanotubes for Improved Breast Cancer Treatment

Quercetin, a flavonoid naturally present in fruits and vegetables, shows promise in treating breast cancer due to its antioxidant and anti-cancer characteristics. However, its clinical use is restricted by poor solubility and bioavailability. This research aims to produce multi-walled carbon nanotubes (MWCNTs) functionalized with polyethylene glycol (PEG) to improve quercetin delivery. The formulation of quercetin-loaded MWCNT-COOH-PEG was optimized using a 3²-factorial design and evaluated for particle size, zeta potential, and entrapment efficiency. The best formulation achieved a particle size of 168.554 nm, a zeta potential of -26.737 mV, and an entrapment efficiency of 98.853%. In vitro release studies showed a cumulative release of 92.75% at pH 5.5 and 98.48% at pH 7.4 over 24 hours, following the Higuchi Model. The formulation demonstrated cytotoxic effects against MCF7 breast cancer cells with an IC ₅₀ value of 41.71 µg/mL and showed efficient cellular uptake. Sterility tests confirmed no microbial growth, and stability studies indicated no significant changes. The quercetin-loaded MWCNT-COOH-PEG formulation appears promising for breast cancer treatment.