Abstract
Background/Objectives: This study aimed to enhance the oral delivery and therapeutic synergy of atorvastatin (AT) and docetaxel (DT) through a metronomic schedule using a transporter-targeted nanoemulsion (NE), with the goal of improving antitumor efficacy and immune modulation. Methods: AT and DT were co-encapsulated in a NE system (AT/DT-NE#E) incorporating deoxycholic acid-DOTAP (D-TAP), biotin-conjugated phospholipid (Biotin-PE), and d-α-tocopherol polyethylene glycol succinate (TPGS) to exploit bile acid and multivitamin transport pathways and inhibit P-glycoprotein efflux. The optimized NE was characterized physicochemically and evaluated for permeability in artificial membranes and Caco-2/HT29-MTX-E12 monolayers. Pharmacokinetics, tumor suppression, and immune cell infiltration were assessed in vivo using rat and CT26.CL25 mouse models. Results: AT/DT-NE#E showed enhanced permeability of AT and DT by 45.7- and 43.1-fold, respectively, across intestinal cell models and improved oral bioavailability by 118% and 376% compared to free drugs. In vivo, oral metronomic AT/DT-NE#E reduced tumor volume by 65.2%, outperforming intravenous AT/DT. Combination with anti-PD1 therapy achieved a 942% increase in tumor suppression over the control, accompanied by marked increases in tumor-infiltrating CD45(+), CD4(+)CD3(+), and CD8(+)CD3(+) T cells. Conclusions: Oral metronomic administration of AT/DT via a dual-transporter-targeted NE significantly improves drug absorption, tumor inhibition, and immune response. This strategy presents a safe and effective approach for colon cancer therapy, particularly when combined with immunotherapy.