Triple-negative breast cancer (TNBC) presents a global health challenge due to its aggressive behavior and limited treatment options. This study explores a novel therapeutic strategy using C-peptide-conjugated solid lipid nanoparticles (C-peptide-SLNs) for targeting paclitaxel (PTX) delivery in TNBC treatment. C-peptide, derived from endostatin, enhances efficacy by targeting overexpressed integrin αvβ3 receptors on TNBC cells. Characterization confirmed suitable particle size, stability, and encapsulation efficiency over 90%, with favorable release profiles for acidic tumor environments. In vitro, C-peptide-SLN-PTX markedly improved cytotoxicity against 4T1 carcinoma cells, with an IC