Formation of Phytosome Containing Silymarin Using Thin Layer-Hydration Technique Aimed for Oral Delivery

Silymarin is a unique flavonoid complex isolated from milk thistle (Silybum marianum) and has been widely used as hepatoprotective agent. Orally administered silymarin will be absorbed rapidly and only 20-50% of silymarin will be absorbed through gastrointestinal tract, resulting on its low bioavailability. Those limitations are due to its poorly soluble either in water and oil and its low intestinal permeability. This study was aimed to develop silymarin-loaded phytosomes to improve silymarin bioavailability with sufficient safety and stability. This system consists of silymarin-phospholipid complex prepared by solvent evaporation method, which was incorporated to formed phytosome shape vesicles using thin layer method with various concentration and molar ratio of silymarin and phospholipid. Phytosome vesicles size was reduced using probe sonication. The result demonstrated that formula with 2% silymarin-phospholipid complex and molar ratio of 1:5 showed the best physical properties with mean vesicle diameter of 133.534 ± 8.76 nm, polidispersity index of 0.339 ± 0.078, entrapment efficiency of 97.169 ± 2.412%, loading capacity of 12.18 ± 0.30%, and good stability after freeze thaw stability test. Analysis of FTIR spectroscopy and DSC was confirmed the presence of physical and chemical interactions between sylimarin and phospholipid complex. Well formed and discrete vesicles of phytosome were revealed by Transmission Electron Microscopy, drug content, and freeze thaw stability test.