A Nanostructured Silica-Lipid Hybrid to Facilitate Oral SN-38-based Chemotherapy

Background: Oral drug administration is preferred by most patients; however this is a challenge for the majority of chemotherapeutic agents that are required to be given via injection, due to their unfavourable physiochemical and biopharmaceutical properties. A silica-lipid hybrid (SLH) carrier formulation has been developed to overcome the water solubility-limited oral absorption of SN-38 and to advance its clinical application as an oral dosage form. Methods: SN-38 SLH particles were engineered by freeze drying a suspension/ emulsion of SN-38, Capmul MCM, soybean lecithin and porous silica nanoparticles (Aerosil 380). SN-38 was also directly loaded in porous silica particles (silica SN-38) and used as a control formulation in in vitro (dynamic drug solubilization) and in vivo (single-dose pharmacokinetics in fasted rats at 10 mg SN-38/kg) studies. Results: The SN-38 SLH solid dosage form contains 0.5 % w/w of drug in a non-crystalline state, as confirmed by DSC and XRD analyses. The internal porous matrix structure of SN-38 SLH provided various biopharmaceutical advantages, including a two-fold improvement in drug solubilization compared to the equivalent physical mixture and superiority bioavailability compared with raw drug and silica SN-38. Conclusion: The SN-38 SLH carrier demonstrates synergistic properties of porous silica and lipid nanoparticle-based delivery systems and is a positive step in achieving safe and effective, needle-free SN-38-based chemotherapy.