Superiority of biomimetic micelle-entrapped nanoporous silica xerogel to deliver poorly water-soluble itraconazole

Micelle-entrapped silica xerogel (M-Silica xerogel) was biomimetically synthesized to combine the advantages of micelles and silica xerogel to load poorly water-soluble drug itraconazole (ITZ). Tween 20, tween 40, and tween 80 were applied to prepare micelles as the templates for M20-Silica xerogel, M40-Silica xerogel, and M80-Silica xerogel, respectively. During the silica frame construction, the surfactant formed a micelle as the porous template, silicon hydroxyl groups interacted with the hydrophilic parts of the micelle, and polyethylenimine catalyzed silica polycondensation owing to its amino groups, resulting in the formation of the M-Silica xerogels. The results showed that the particle size of the sub-particles from the M40-Silica xerogel was larger than from the M20-Silica xerogel, and the M80-Silica xerogel was the largest among these three samples, demonstrating that the emulsifying ability had a direct impact on the particle size of the M-Silica xerogel. The M-Silica xerogel had a large pore size in the range of 10–50 nm. Small mesopores (2–5 nm) dominated the pore size of the M20-Silica xerogel, while medium mesopores (5–10 nm) occupied most the pore distribution of the M40-Silica xerogel, and large mesopores (10–50 nm) shouldered most the pore distribution for the M80-Silica xerogel. Among these three drug-loaded carriers, the M40-Silica xerogel with the largest amount of medium mesopores presented the best ITZ-release behavior, demonstrating that medium mesopores facilitated drug release, while small mesopores impeded drug release and large mesopores were not favorable to retaining amorphous drugs in the pores.