Optimized microemulsions and solid microemulsion systems of simvastatin: characterization and in vivo evaluation

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems

Background:

• Simvastatin (SMV) is a water-insoluble drug used to treat hyperlipidemia.
• Improving the oral bioavailability and efficacy of simvastatin is a significant challenge in pharmaceutical development.

Purpose of the Study:

• To develop and characterize solid microemulsions (SMEs) for enhanced oral delivery of simvastatin (SMV).
• To evaluate the in vitro and in vivo performance of simvastatin-loaded SMEs.

Main Methods:

• Construction of pseudo-ternary phase diagrams for microemulsion (ME) optimization.
• Preparation of SMEs by adsorbing liquid MEs onto colloidal silicon dioxide.
• Characterization of MEs and SMEs including globule size, powder properties, dissolution, and in vivo efficacy in hyperlipidemic rats.

Main Results:

• X-ray diffraction and scanning electron microscopy confirmed the amorphization and solubilization of simvastatin within the SMEs.
• Dissolution studies showed a significant increase in simvastatin release compared to the plain drug.
• In vivo studies demonstrated a significant reduction in total cholesterol levels in hyperlipidemic rats treated with the SMEs.

Conclusions:

• Solid microemulsions effectively enhance the dissolution and oral delivery of poorly water-soluble drugs like simvastatin.
• The developed SMEs show promising potential for improving the efficacy of simvastatin in treating hyperlipidemia.