Recent patents in siRNA delivery employing nanoparticles as delivery vectors

Small interfering RNAs (siRNAs) are rapidly emerging as new therapeutic tools for the treatment of some of the deadly diseases such as cancer. However, poor cellular uptake and instability in physiological milieu limit its therapeutic potential, hence there arises a need of a delivery system which can efficiently and repeatedly deliver siRNA to the target cells. Nanoparticles have shown immense potential as suitable delivery vectors with enhanced efficacy and biocompatibility. These delivery vectors are usually few nanometers in size, which not only protects siRNA against enzymatic degradation but also leads to tissue and cellular targeting. Nanoparticles prepared from various cationic polymers like polyethylenimine, and chitosan have been largely exploited as they bear several advantages such as, ease of manipulation, high stability, low cost and high payload. This review summarizes some of the recent patents on siRNA delivery employing polymer or lipid-based nano-vectors for therapeutic applications.