Liposomal co-delivery of β-carotene and doxorubicin for enhanced colorectal-cancer therapy.

Colorectal cancer (CRC) remains a major cause of cancer-related mortality, motivating delivery systems that retain antitumor activity while limiting off-target toxicity. We engineered neutral multilamellar soy-lecithin liposomes co-encapsulating β-carotene (BC) and doxorubicin (DOX). Thin-film hydration produced vesicles with a DLS Z-average of 122.4 ± 83.4 nm (PDI = 0.534) and ζ-potential of - 25.6 ± 8.0 mV, and a TEM diameter of 184 ± 34 nm, with > 90% entrapment efficiency for both cargos. In HCT-116 cells the formulation preserved DOX potency (IC₅₀, µg mL⁻, mean ± SD: free DOX 610.9 ± 11.4; DOX-Lipo 614.0 ± 1.8; BC-DOX-Lipo 618.9 ± 5.8) and remained ~ 1.5-fold more active than BC alone (free BC 960.6 ± 13.6; BC-Lipo 951.8 ± 18.8). Annexin V/PI flow cytometry showed that BC-DOX-Lipo achieved the highest total apoptosis (44.51 ± 4.45%) and deep G₀/G₁ arrest (92.06 ± 9.2%), reducing S-phase to 6.37 ± 0.60% (p = 0.0186 vs DOX-Lipo). Alkaline comet analysis indicated that co-delivery modestly attenuated DOX-associated DNA fragmentation (tailed cells 11.43 ± 0.45% for BC-DOX-Lipo vs 16.27 ± 0.25% for DOX-Lipo, p < 0.001), consistent with BC's redox buffering. Differential scanning calorimetry and FTIR supported drug-bilayer interactions: BC slightly increased Tm and acyl-chain order, whereas DOX disrupted cooperativity; co-loading shifted T to 37.84 °C and broadened the transition, indicating a more fluid bilayer at 37 °C. In-silico ADMET profiling (contextual, not in-vivo PK) highlighted superior oral absorption and BBB penetration for BC and negligible oral uptake for DOX; docking predicted higher DOX affinities across Bcl-2, β-catenin, P-glycoprotein, and topoisomerase II (e.g., - 9.06 to - 9.30 kcal mol⁻) relative to BC (≈ - 7.6 to - 7.8 kcal mol⁻). Overall, liposomal co-delivery maintains DOX cytotoxicity while strengthening G₁/S checkpoint blockade and increasing programmed cell death, with partial moderation of DNA fragmentation. These in-vitro data motivate stability optimization and in-vivo evaluation in CRC models.