Breast cancer is a significant public health issue in both developed and developing countries. Chemotherapy is the primary method of treatment to eliminate drug-resistant cells and prevent progenitor cancer cell growth. Polycaprolactone (PCL) is an excellent candidate for sustained drug delivery due to its amphiphilic nature, semi-crystalline form, biodegradability, biocompatibility, and slow drug release profile. This significant property has motivated their relevance, particularly in the area of anticancer drug delivery applications in the various nanoaggregates. Doxorubicin (DOX) and 5-fluorouracil (5-FU) are common anti-cancer drugs used for breast cancer treatment that they can easily incorporate into PCL. In this study, we synthesized the copolymer of PCL, PCL-DOX-FU, and performed characterization tests (Fourier transform infrared (FTIR), scanning electron microscopy (SEM)).We prepared a breast cancer cell line and evaluated the viability of cultured cells using the MTT test in different treatment groups (PCL, DOX-5FU, DOX, FU) at three different time points (24 h, 48 h, 72 h), and at different concentrations (9, 25, 50, 70 mu g/ml). Additionally, we determined the expression rate of Bax and BCL-2 as apoptotic activator genes in treatment groups via real-time PCR techniques. Our data confirms that there are interactions between the active groups in PCL and DOX, as well as 5-FU drugs. After 72 h, a significant decrease was observed at concentrations of 50 and 70. Furthermore, the expression levels of Bcl2 and Bax were significantly reduced in cells treated with DOX, 5-FU, and DOX-5-FU-PCL nanoparticles. Our objective was to produce a nanocarrier system by coating magnetic nanoparticles with FOX-5-FU-PCL and evaluate its impact on the survival of MDA-MB-231 breast cancer cells. Our findings demonstrate that this method was highly successful in enhancing drug delivery efficiency for cancer treatment. However, further investigations are necessary to fully understand the safety and efficacy of these nanoparticles for clinical use.