Lipid Nanocarriers for Oral Delivery of Serenoa repens CO2 Extract: A Study of Microemulsion and Self-Microemulsifying Drug Delivery Systems

The aim of this study was the development and characterization of lipid nanocarriers using food grade components for oral delivery ofSerenoa repensCO2extract, namely microemulsions (MEs) and self-microemulsifying drug delivery systems (SMEDDSs) to improve the oral absorption. A commercial blend (CB) containing 320 ofS. repensCO2extract plus the aqueous soluble extracts of nettle root and pineapple stem was formulated in two MEs and two SMEDDSs. The optimized ME loaded with the CB (CBM2) had a very low content of water (only 17.3%). The drug delivery systems were characterized by dynamic light scattering, transmission electron microscopy, and high-performance liquid chromatography (HPLC) with a diode-array detector analyses in order to evaluate the size, the homogeneity, the morphology, and the encapsulation efficiency.β-carotene was selected as marker for the quantitative HPLC analysis. Additionally, physical and chemical stabilities were acceptable during 3 wk at 4 °C. Stability of these nanocarriers in simulated stomach and intestinal conditions was proved. Finally, the improvement of oral absorption ofS. repenswas studiedin vitrousing parallel artificial membrane permeability assay. An enhancement of oral permeation was found in both CBM2 and CBS2 nanoformulations comparing with the CB andS. repensCO2extract. The best performance was obtained by the CBM2 nanoformulation (~ 17%) predicting a 30 - 70% passive oral human absorptionin vivo.