Pharmaceutical Nanoplatforms Based on Self-nanoemulsifying Drug Delivery Systems for Optimal Transport and Co-delivery of siRNAs and Anticancer Drugs.

Small interfering RNAs (siRNAs) have the ability to induce selective gene silencing, although siRNAs are vulnerable to degradation in vivo. Various active pharmaceutical ingredients (APIs) are currently used as effective therapeutics in the treatment of cancer. However, routes of administration are limited due to their physicochemical and biopharmaceutical properties. This research aimed to develop oral pharmaceutical formulations based on self-nanoemulsifying drug delivery systems (SNEDDS) for optimal transport and co-delivery of siRNAs related to cancer and APIs. Formulations were developed using optimal mixing design (Design-Expert 11 software) for SNEDDS loading with siRNA (water/oil emulsion), API (oil/water emulsion), and siRNA-API (multiphase water/oil/water emulsion). The final formulations were characterized physicochemically and biologically. The nanosystems less than 50 nm in size had a drug loading above 48 %. The highest drug release occurred at intestinal pH, allowing drug protection in physiological fluids. SNEDDS-siRNA-APIs showed a twofold toxicity effect than APIs in solution and higher transfection and internalization of siRNA in cancer cells with respect to free siRNAs. In the duodenum, higher permeability was observed with SNEDDS-API than with the API solution, as determined by ex-vivo fluorescence microscopy. The multifunctional formulation based on SNEDDS was successfully prepared, siRNA, hydrophobic chemotherapeutics (doxorubicin, valrubicin and methotrexate) and photosensitizers (rhodamine b and protoporphyrin IX) agents were loaded, using a chitosan-RNA core, and Labrafil® M 1944 CS, Cremophor® RH40, phosphatidylcholine shell, forming stable hybrid SNEDDS as multiphasic emulsion, suitable as co-delivery system with a potent anticancer activity.