siRNA Vehicles for High Endosomal Escapability

Small interfering RNA (siRNA) is a novel therapeutic modality for the treatment of intractable diseases; however, the development of a useful siRNA delivery vector is imperative for clinical use. Since siRNA works in the cytoplasm, the ability of the carrier to escape destruction in the endosomes is a highly required characteristic for the induction of a high knockdown effect. Here, we describe the step-by-step procedure for the evaluation of high endosomal escapability. The vector that has pH-responsive characteristics at around pH = 6.2–6.5 is important for the high endosomal escape.