Bambara Starch Essay

The physical properties of the starch are given in Table 2. Particle size analysis suggested that the native form of the starch possessed the lowest values of mean projected particle diameter, d for the botanical starches. Native Bambara starch granules (8.69µm) appeared comparatively smaller in size than those of pregelatinized granules (9.35µm) and carboxymethylated granules (13.23µm). Modification significantly increased the mean projected diameter of native Bambara starch, especially carboxymethylation. The increased particle size of the pregelatinised starches may be attributed to swelling of the starch granules due to gelatinization and resultant leaching of the amylose. Ibuprofen had low particle density (1.06gcm-1) and mean projected diameter of 44.15 µm. It has poor flowability and is highly cohesive in nature, which explains its poor compression properties. Hence, ibuprofen powder on its own cannot be easily compacted and requires the use of excipients with good flow and densification properties.

3.2 Heckel parameters

The results of Heckel relationships are presented in Table 3 and Fig. 1. The predominantly linear and almost parallel Heckel plots were obtained from plots of ln (1/1-D) versus applied pressure for the pure starches (50% starch), are suggestive of type A

Do is the relative density of the powder bed when the applied pressure equal zero and describes the initial rearrangement phase of densification. Da is the total degree of densification achieved at both zero and low pressures, following rearrangement processes before any appreciable amount of interparticulate bonding occurs. Db is the relative density of the powder at low pressures, that is the phase of densification following application of low pressures due to rearrangement and/ or fragmentation of particles before appreciable deformation of particles occurs