Unveiling the potential of solid lipid nanoparticles of apigenin-Cu(II) coordinated nanocomplex in colon cancer

To engineer biocompatible, colon-targeted delivery vehicle utilizing octadecanol-dextran (Odl-Dex)-coated apigenin-copper (Apg-Cu(II)) loaded solid lipid nanoparticles (SLNs). The main research study was based on enzyme-responsive system to prevent premature gastrointestinal drug degradation while maximizing localised therapeutic potential against colon cancer. The Apg-Cu(II) SLNs were formulated via hot-melt emulsification and surface-coated with Odl-Dex. The nanoparticles were characterised for particle size, surface charge, and entrapment efficiency (%). Enzyme-triggered release was evaluated using simulated gastrointestinal fluid with dextranase. In vitro cytotoxicity and cellular apoptosis were assessed on human HCT-116 colon cancer cells, followed by in vivo pharmacokinetic evaluation in Wistar rats to determine oral bioavailability. The optimised Odl-Dex-coated Apg-Cu(II) SLNs exhibited the particle size of 374 ± 2.03 nm, surface charge of -25.6 ± 0.36 mV, and entrapment efficiency of 84.54 ± 0.05%. The formulation maintained robust stability in gastric and intestinal environments, triggering precise release upon exposure to colonic dextranase. Cu(II) complexation significantly enhanced the anticancer efficacy, lowered the IC₅₀ against HCT-116 cells to 0.8 ± 0.6 µg/mL compared to free Apg (3.00 ± 1.53 µg/mL) and Apg-Cu(II) loaded SLNs (1.5 ± 0.2 µg/mL), and then, profoundly induced sub-G1 phase apoptosis. Furthermore, in vivo studies demonstrated a remarkable improvement in oral bioavailability (AUC: 484.28 ± 5.21). Apg-Cu(II)-Odl-Dex SLNs effectively bypass premature upper gastrointestinal release and significantly improve oral bioavailability. This novel and enzyme-modulated nanocarrier serves as a highly promising and advanced targeted therapeutic strategy for colon cancer.