A Dual-Drug Nanosuspension of Bufalin and Quercetin Exhibits Potent Anti-Hepatocellular Carcinoma Activity In vitro and In vivo

Introduction: Both bufalin (BF) and quercetin (QUE) have demonstrated significant antitumor potential. However, they suffer from poor solubility and low bioavailability, which largely limit their clinical application. In order to increase the antitumor activity of BF and QUE by synergistic effect, BF and QUE co-loaded nanosuspension (BF-QUE NS) was developed. Methods: The MTT method was used to determine the viability of HepG2 cells after treatment with BF and QUE at different mass ratios, and the optimal combination ratio was screened. BF-QUE NS was prepared by the anti-solvent precipitation method, and the single factors affecting its preparation were investigated to optimize the formulation and preparation process of the best combined NS. BFQUE NS was characterized by observing morphology, measuring particle size and zeta potential, Xray diffraction, differential scanning calorimetry, and drug release in vitro. Cytotoxicity was detected using the MTT method; the uptake of BF-QUE NS by HepG2 cells was observed by laser confocal microscopy and flow cytometry; apoptosis of HepG2 cells was detected by flow cytometry. BF-QUE NS was systematically characterized, and H22 tumor-bearing mice were further used to investigate the targeting distribution, antitumor effect. Results: The optimal synergistic ratio of BF to QUE was 3:2. The mass ratio of BF and QUE in BFQUE NS was 1.47:1. The optimized BF-QUE NS exhibited an average particle size of 238.4 ± 2.1 nm, polydispersity index of 0.250 ± 0.004, zeta potential of -22.2 ± 0.3 mV, and presented good short-term physical stability. In vitro and in vivo experiments demonstrated that BF-QUE NS exhibited significant liver tumor-targeting efficacy, achieving an inhibition rate of 72.59% in H22 tumorbearing mice, along with high safety profiles. Discussion: BF-QUE NS provides a practical solution to the delivery challenges of poorly soluble anti-cancer drugs. Conclusion: The prepared BF-QUE NS enhanced the drug solubility and promoted the targeted accumulation in tumors, thereby strengthening the synergistic anti-tumor effect of BF and QUE. BFQUE NS shows potential for clinical application as an anti-liver tumor drug.