In Vitro Release and Bioavailability of Silybin from Micelle-Templated Porous Calcium Phosphate Microparticles

Developing a promising carrier for the delivery of poorly water-soluble drugs, such as silybin, to improve oral absorption has become a very worthy of consideration. The goal of this study was to prepare a novel porous calcium phosphate microparticle using povidone-mixed micelles as template while evaluating its in vitro and in vivo properties with silybin as a model drug. The particle characterization, in vitro drug release behavior, and pharmacokinetic parameters of the prepared silybin-loaded calcium phosphate microparticle were investigated. The mean particle size was found to be 3.54 ± 0.32 μm with a rough surface porous structure. Additionally, the silybin-loaded calcium phosphate microparticle compared with the free silybin showed a prolonged 72-h release in vitro and a higher C max (418.5 ± 23.7 ng mL(-1)) with 167.5% oral relative bioavailability. A level A in vitro-in vivo correlation (IVIVC), established for the first time, demonstrated an excellent IVIVC of the formulated silybin in oral administration. In conclusion, this povidone-mixed micelle-based microparticle was successfully prepared to enhance the oral bioavailability of silybin. Therefore, application of this novel porous calcium phosphate microparticle holds a significant potential for the development of poorly water-soluble drugs.

Hepatoprotective effect of flavonoids from Cirsium japonicum DC on hepatotoxicity in comparison with silymarin

Cirsium japonicum DC is a perennial plant that is widely distributed throughout China. Flavonoids are the major active constituents of C. japonicum, which has been reported to possess many bioactivities. This study was designed to investigate the protective effects of flavonoids from C. japonicum against liver injury using carbon tetrachloride (CCl4)-induced hepatocyte injury, with silymarin as a positive control. Silymarin is a mixture of flavonoids from Silybum marianum, a traditional European food plant with clear hepatoprotective effects. The results indicated that the pretreatment with C. japonicum flavonoids could significantly reverse CCl4-induced L02 cell viability decrease similarly to silymarin. Analysis of flavonoids of C. japonicum and silymarin by HPLC showed that these two mixtures may contain one common component, which may be the major active ingredient responsible for their hepatoprotective effects. It is concluded that C. japonicum could be developed into functional foods with hepatoprotective efficacy, similarly to S. marianum.

Silymarin-Loaded Nanoparticles Based on Stearic Acid-Modified Bletilla striata Polysaccharide for Hepatic Targeting

Silymarin has been widely used as a hepatoprotective drug in the treatment of various liver diseases, yet its effectiveness is affected by its poor water solubility and low bioavailability after oral administration, and there is a need for the development of intravenous products, especially for liver-targeting purposes. In this study, silymarin was encapsulated in self-assembled nanoparticles of Bletilla striata polysaccharide (BSP) conjugates modified with stearic acid and the physicochemical properties of the obtained nanoparticles were characterized. The silymarin-loaded micelles appeared as spherical particles with a mean diameter of 200 nm under TEM. The encapsulation of drug molecules was confirmed by DSC thermograms and XRD diffractograms, respectively. The nanoparticles exhibited a sustained-release profile for nearly 1 week with no obvious initial burst. Compared to drug solutions, the drug-loaded nanoparticles showed a lower viability and higher uptake intensity on HepG2 cell lines. After intravenous administration of nanoparticle formulation for 30 min to mice, the liver became the most significant organ enriched with the fluorescent probe. These results suggest that BSP derivative nanoparticles possess hepatic targeting capability and are promising nanocarriers for delivering silymarin to the liver.