Physicochemical evaluation of sorghum starch co-processed with colloidal silicon dioxide

Abstract

The aim of this study was to evaluate the physicochemical properties of sorghum starch (extracted from Sorghum bicolor grains) co-processed with colloidal silicon dioxide and its potential as an excipient in pharmaceutical formulations. The obtained sorghum starch was co-processed with colloidal silicon dioxide to form a new excipient. The particle size distribution, bulk density/tapped density, Carr’s index, Hausner’s ratio, angle of repose, flow rate, moisture content, swelling capacity and moisture sorption capacity of the co-processed excipient were investigated. The
compatibility of the sorghum starch with the colloidal silicon dioxide was examined using Fourier transform infra-red spectroscopy (FTIR), while the excipient morphology was evaluated using Scanning electron microscopy (SEM). The co-processed excipient showed better flow properties than the native sorghum starch with Carr’s index, Hausner’s ratio and flow rate of 21.0 %, 1.27 and 1.79 g/sec respectively, compared to 28.1 % 1.39 and 1.45 g/sec for the native starch respectively. The SEM result shows changes in the surface morphology including changes in the size, shape and porosity of the particles. The FTIR investigation suggests that the co-processed ingredients are compatible. The study revealed that the co-processed excipient possessed fundamental characteristics that would make it suitable as a pharmaceutical excipient for solid dosage forms especially as a disintegrant due to its high water absorption and swelling capacity.

Keywords: Sorghum starch, colloidal silicon dioxide, co-processing, excipient