Combinatorial Anti-Mitotic Activity of Loratadine/5-Fluorouracil Loaded Zein Tannic Acid Nanoparticles in Breast Cancer Therapy: In silico, in vitro and Cell Studies

Introduction: Chemotherapy, the first approach in breast cancer management, is limited owing to systemic toxicity and drug resistance. For instance, 5-fluorouracil in recommended doses cause severe side effects, highlighting the urgent necessity of finding more effective and safer combinations. Hence, this study aims to develop biocompatible natural-based nanocarriers for the co-delivery of loratadine, an antihistaminic drug along with 5-fluorouracil in order to enhance the anticancer efficacy while reducing the required dose of 5-fluorouracil. Methods: In silico virtual screening was performed to examine the probable molecular interactions between loratadine or 5-fluorouracil, individually with two different polymers, chitosan and zein, to determine the most suitable carrier system. Zein exhibited superior binding affinity compared to chitosan. Nanoparticle optimization was conducted using a Box-Behnken design with zein, tannic acid, and either loratadine or 5-fluorouracil concentration as independent variables. The optimized formulations were characterized by dynamic light scattering, entrapment efficiency, morphology, in-vitro release, followed by cytotoxicity, apoptosis, and cell-cycle analyses in MCF-7 cells. Results: The optimal formulation consisted of zein (50 mg), tannic acid (131.93 mg), and loratadine or 5-fluorouracil (5 mg). The optimized formulation of Loratadine loaded nanoparticles (NPs) showed a particle size of 197 nm, polydispersity index (PDI) of 0.153, zeta potential of –21.78 mV, and entrapment efficiency of 61.33%. Furthermore, the optimized 5-fluorouracil loaded nanoparticles exhibited a particle size of 231 nm, 0.170 for PDI, zeta potential of –24.01 mV, and EE of 74.91% for entrapment efficiency. The sustained drug release profile exhibited a controlled pattern over 24–48 h. Flow cytometry results showed that the mixed nanoparticles exhibited potent cytotoxicity equivalent to 5-fluorouracil loaded nanoparticles alone despite containing only half the 5-fluorouracil dose, confirming a potential synergistic effect. Conclusion: These findings confirmed the potential of drug-loaded nanoparticles as promising drug delivery systems for breast cancer management.