Silica from Rice as New Drug Delivery Systems

Abstract

The pharmaceutical industry has seen an increased need of carriers or excipients design that allows the controlled release of a drug in the human body. The main role of an excipient is to carry the drug for its administration under therapeutic index. Among the new generation of excipients, the ordered mesoporous silica (MS) presents several advantages, such as excellent biocompatibility, good adsorption capacity, and precise control in the drug delivery. However, the high cost of synthesis of mesoporous silica restricts its use to industrial applications; therefore, a low-cost procedure is necessary for widespread use. Biogenic silica from rice husk (SiO 2 -rice) could be a new choice as a drug delivery system. This silica is obtained from an acid leaching of rice husk followed by calcinations processes at low temperatures; these conditions produce silica with good adsorption properties, similar to those of MS. In consequence, the excipient behavior of SiO 2 -rice was assessed using folic acid as the model drug, displaying an 18.5% of absorption in the SiO 2 -rice pores, while MS absorbed around 19%. The drug release profiles were similar for both the silicas, suggesting that SiO 2 -rice could be a low-cost, similar yield excipient for drugs similar to folic acid.