The present study investigates the encapsulation of a PI3‐Kδ/HDAC6 dual inhibitor into hybrid block copolymers (polylactic acid‐methoxy polyethylene glycol; polylactic acid‐polyethylene glycol‐polypropylene glycol‐polyethylene glycol‐polylactic acid) (HSB‐510) as a delivery system to target PI3‐Kδ and HDAC6 pathways in breast cancer cells. The gene discussed is HDAC6; the disease is breast cancer.