Oral bioavailability of silymarin phytocomplex formulated as self-emulsifying pellets

Area of Science:

• Pharmaceutical Technology
• Drug Delivery Systems
• Natural Product Chemistry

Background:

• Milk thistle extract (silymarin) is a valuable phytotherapeutic agent.
• Improving the oral bioavailability of silymarin presents a significant challenge.
• Solid self-emulsifying systems offer a promising approach for enhancing drug delivery.

Purpose of the Study:

• To develop novel solid self-emulsifying pellets for milk thistle extract (silymarin) delivery.
• To optimize the formulation and manufacturing process using extrusion/spheronisation.
• To evaluate the technological and biopharmaceutical properties of the developed pellets.

Main Methods:

• Pellets were prepared using a self-emulsifying system (SES) with excipients like microcrystalline cellulose and lactose monohydrate.
• Extrusion/spheronisation was employed, with an experimental design to screen 13 formulations.
• Pellet characterization included size, shape, density, and crushing force, followed by in vitro dissolution and in vivo pharmacokinetic studies in rats.

Main Results:

• Formulation 7 yielded pellets with optimal morphological and technological characteristics.
• In vivo studies demonstrated a significant increase in oral bioavailability (>100-fold) of silymarin components.
• Enhanced absorption was primarily attributed to increased lymphatic uptake.

Conclusions:

• Extrusion/spheronisation is a viable technology for producing high-quality self-emulsifying pellets.
• The developed pellets effectively improve the oral bioavailability of milk thistle extract.
• The enhanced lymphatic absorption pathway is key to the improved in vivo performance.