Rice Hulk Ash as an Alternative Source of Silica for the Production of Medicine Release Systems – A Review and New Perspectives

Abstract

Rice husk ash (CCA) is a residue generated from burning the husk, obtained after processing rice, for energy generation, and may contain around 80 -98% w/w amorphous silica depending on the conditions of burn. Obtaining silica can be carried out through different processes, however, as it is extracted from industrial waste, with a renewable raw material source, it makes the process economically and ecologically viable. Amorphous silica has been applied in several areas of science and technology, however, due to its physical-chemical characteristics, biocompatibility and chemical inertness, work has been carried out using silica as vehicles for transporting medicines. Release systems aim to control the rate and time of release as well as the location of where the drug must act, thus increasing the efficiency and safety of therapeutic treatment, with the reduction of dosage and side effects, respectively. The systems are prepared by loading bioactive molecules into the system and are analyzed using various analytical techniques. In this review, a survey of publications focused on the production and characterization of silica particles was carried out with the aim of obtaining support for medicines. After analyzing fifteen articles, it was concluded that medicines have the ability to be adsorbed on amorphous materials or in dispersions. Colloidal solutions containing silica, more precisely airgel, are the most widely used medium, as they present requirements for an efficient drug release system, such as low density, high porosity and large specific area, resulting in high adsorption capacity and release control. of the drug, as well as greater efficiency in the interaction between the biological fluid and the polymeric matrix. Ibuprofen was used as a model drug to carry out studies on the loading and release efficiency of the devices. The studies were carried out exclusively on a laboratory scale.