Robust Silica Aerogel Microspheres from Rice Husk Ash to Enhance the Dissolution Rate of Poorly Water-Soluble Drugs

The present paper demonstrates the capability of specially prepared robust silica aerogel microspheres (RSAMs) to enhance the dissolution rate of poorly water-soluble drugs. A sol-gel/mineral oil emulsion method has been developed for RSAMs from rice husk ash (RHA), a biogenic source. The particles were characterized for their Brunauer-Emmett-Teller (BET) specific surface area, Barrett, Joyner and Halenda (BJH) pore volume and pore diameter, and morphology by optical microscopy and scanning electron microscopy (SEM). The dissolution rate of ibuprofen, a poorly water-soluble drug, was investigated by adsorbing it onto RSAMs upon dissolving it in supercritical carbon dioxide (scCO(2)) at 150 bar and 40 degrees C. This resulted in a loading of similar to 0.13 g ibuprofen/g loaded RSAMs in 24 h. X-ray diffraction analysis was used to characterize the nature of the adsorbed ibuprofen onto RSAMs. It was observed that the loaded drug on the aerogels is in amorphous form. An in vitro drug-release kinetic studies confirmed a significant enhancement in the dissolution rate, namely similar to 100% of the loaded ibuprofen released as compared to that of similar to 11% of crystalline ibuprofen in 15 min.