Development of self-microemulsifying tablets containing dutasteride for enhanced dissolution and pharmacokinetic profile

This study aimed to develop self-microemulsifying tablets containing the hydrophobic drug dutasteride for easy administration and high in vivo absorption. The candidate lipids and surfactants were formulated into a self-microemulsifying drug delivery system (SMEDDS), and their mean droplet size upon dilution was evaluated. The SMEDDS containing Capmul® MCM, Captex® 355, and Cremophor® EL showed improved dissolution in the gastric medium when compared to the dissolution of the conventional product (Avodart®) and the raw drug. Among the various porous silicon microparticles for solidifying SMEDDS, Neusilin® US2 showed favorable properties in terms of maximum adsorption capacity, powder flow, and compaction. However, the amount of drug released from the solidified SMEDDS after the adsorption process was lower than that of liquid SMEDDS, indicating incomplete desorption. After observing the effect of the solid-to-liquid ratio and pre-filling the pores with blank SMEDDS, complete desorption was obtained when the pores were first adsorbed with polyvinylpyrrolidone. The self-microemulsifying tablets exhibited improved bioavailability (29.9% and 15.2%) compared to the conventional soft gelatin product. Therefore, the proposed system could successfully solubilize the hydrophobic drug while maintaining rapid and complete desorption from the solid carrier, resulting in enhanced in vivo performance.