HER2, a tyrosine kinase receptor, is amplified in HER2-positive breast cancer, driving cell signaling and growth. This study aimed to combat multidrug resistance in Dox-insensitive breast adenocarcinoma by creating a nanoformulation therapy with a tyrosine kinase inhibitor. Human serum albumin (HSA) was conjugated with α-D-tocopherol succinate to form nanoaggregates loaded with lapatinib (Lapa). The resulting Lapa@HSA(VE) NPs were 117.2 nm in size and demonstrated IC50 values of 10.25 μg/ml on MCF7 (S) and 8.02 μg/ml on MCF7 (R) cell lines. Lapa@HSA(VE) NPs showed no hepatotoxicity, unlike free Lapa, as seen in acute toxicity studies in rats.