¹Ege University, Faculty of Pharmacy, Radiopharmacy Department, Bornova İzmir DOI : 10.29228/jrp.148 The current study aims to develop new freeze-dry kits containing Imatinib and different chelating agents for breast cancer treatment and diagnosis as theranostics. Four formulations (Kit-1, Kit-2, Kit-3, and Kit-4) were prepared, and the characterization of formulations was assessed utilizing particle size, polydispersity index, zeta potential, fourier transform infra-red analysis, ultraviolet spectrum analysis, differential calorimetry, and thermogravimetric analysis. They were also evaluated for stability at different storage conditions and cytotoxicity effect on fibroblast NIH-3T3 cells. The particle size, polydispersity index, and zeta potential of developed formulations were found to be between 6953.6 ±131.6 and 5888.3 ± 131.6 nm, 0.481 ± 0.24 and 0.319 ± 0.18, -594.5±59.6 and -477.3 ± 25.32 mV, respectively. Fourier transform infra-red analysis, ultraviolet spectrum, differential calorimetry, and thermogravimetric analysis have proven that IMT and chelating agents formed complexes in kit formulations. Also, they exhibited stable facility and above 90% of cell viability on fibroblast NIH-3T3 cells. By the result of our study, kit formulations can be a favorable drug delivery system in the treatment and diagnosis of breast cancer with a non-toxic effect on healthy cells. Keywords : Imatinib; cytotoxicity; breast cancer; chelating agents; theranostic