Physicochemical properties of two brands of pregelatinised starch from maize cultivated in Nigeria

Abstract

The aim of this work was to investigate the physicochemical properties of two brands of pregelatinised starch processed differently from the same starting material. Particle size distribution, microscopy, photomicrography, flow properties, compactibility and purity tests were carried out on the brands [Evansgel® powder (EGP) and Evansgel® flakes (EGF)] processed by a company in Nigeria from locally cultivated maize. A commercially available pregelatinised starch (PS) and a traditional starch (CS) were employed for comparison. 68% each of EGP and PS were retained on sieve size 100 and their particle size ranged between 30 and 130µm. The packing and flow characteristics of EGP and PS such as bulk densities of EGP and PS were the same, being 0.374g/cm 3 while their tapped densities were 0.548 and 0.521g/cm3 respectively. EGF on the other hand had most of the particles (98%) retained on sieve number 40 and the particle size range was between 50 and 200µm. Compact of PS and EGP had hardness of 3.5 and 5.9N respectively and their friability was 6.57 and 4.55% respectively. EGF had a friability value of 100% and could not form good compacts. It was concluded that processing techniques influenced their physicochemical properties. These differences are likely to play a role in the use to which these excipients can be put in pharmaceutical formulations. EGP and PS showed better similarities in their physicochemical properties than EGF with either of them and consequently EGP may be a good substitute for PS as a tablet excipient. Key words : Pregelatinised starch; Physicochemical properties; Tabletting excipients Journal of Pharmacy and Bioresources Vol. 2 (1) 2005: 20-28