Objective To construct and optimize tanshinone II_A (TS II_A)-loaded micelles modified with a cardiomyocyte-targeting peptide CTP (APWHLSSQYSRT) (CTP-Ms/TS II_A), optimize their formulation, and evaluate their physicochemical properties and cardioprotective effects in vitro. Methods CTP-Ms/TS II_A were prepared using the film hydration method. A Box-Behnken response surface design was applied to optimize formulation parameters (Soluplus concentration, TPGS₁₀₀₀ concentration, hydration temperature) with encapsulation efficiency as the evaluation index. Particle size, ζ potential, and morphology of micelles were characterized by dynamic light scattering and transmission electron microscopy (TEM). Critical micelle concentration (CMC) was determined using pyrene as a probe, and storage and serum stability were assessed. Cellular uptake was investigated in H9c2 cardiomyocytes by flow cytometry and fluorescence microscopy. In an isoproterenol-induced H9c2 injury model, intracellular reactive oxygen species (ROS), mitochondrial membrane potential, cell viability, and apoptosis were evaluated by DCFH-DA, JC-1, calcein/PI staining, and CCK-8 assays. Results The optimal preparation parameters were determined as: formulation volume 5 mL, Soluplus concentration 12 g/L, TPGS₁₀₀₀ concentration 5 g/L, and hydration temperature 40 ℃. The CTP-Ms/TS II_A prepared under these conditions (with membrane materials including TS II_A, Soluplus, TPGS₁₀₀₀, DSPE-PEG₂₀₀₀, and DSPE-PEG₂₀₀₀-CTP) achieved a high EE of (90.64 ± 1.01)% (n＝3). The micelles exhibited a particle size of (89.30 ± 0.76) nm, a ζ potential of (−0.033 ± 0.150) mV, and a critical micelle concentration of 42.8 μg/mL, with good stability. Compared with non-targeted micelles, CTP-Ms/TS II_A exhibited significantly enhanced uptake in H9c2 cells, more effective ROS scavenging, restoration of mitochondrial membrane potential, and improved cell survival. Conclusion CTP-Ms/TS II_A with stable physicochemical properties were successfully prepared, and their cardiac-targeting and cardioprotective potential were verified by in vitro experiments. This work provides a new experimental basis and potential delivery strategy for the application of TS II_A in the prevention and treatment of cardiovascular diseases.

tanshinone II_A  /  cardiomyocyte targeting  /  targeted drug delivery  /  Box-Behnken response surface methodology  /  micelles  /  cardiomyocyte-targeting peptide  /  critical micelle concentration