Physicochemical properties of <i>Anacardium occidentale</i> gum and its application as binder in the formulation of metronidazole tablets

Abstract

This study attempts to investigate the comparative binding efficiency of Anacardium occidentale (cashew nut tree) gum, acacia gum and polyvinyl pyrrolidone (PVP) in tablet formulation. The cashew gum powder was characterized for flow properties and results obtained were comparable to those of polyvinyl pyrrolidone and acacia powders. Metronidazole granules were prepared with different concentrations of the gum as binder by wet granulation method. The granules were evaluated for their flow properties and were found to be suitable to be compressed into tablets as evidenced by the average values of their bulk density (0.46 g/ml), tapped density (0.54 g/ml), Hausner ratio (1.17) and Carr’s index (14.5). The physicochemical properties of the compressed tablets were evaluated and the mean values of weight variation (g), tablet thickness (mm) and diameter (mm) were satisfactory; the friability of the tablets formulated with the gum was concentration dependent with those of 1% ^w/_v, 1.5% ^w/_v, 2% ^w/_v and 2.5% ^w/_v having values of 2.42, 1.01, 0.75 and 0.63 respectively. At the concentrations employed, the hardness of the tablets was satisfactory ranging from 4.0 to 5.4 (kgf); the disintegration time complied with the BP specification of not more than 15 minutes for uncoated tablets. At all concentrations, tablets formulated with cashew gum as binder released between 71.5 to 79.5% of the drug in 45 min. These values compared with those of PVP (71.0 to 79.0%) and Acacia gum (72.8 to 80.1%) at 45 min. The cashew gum was found to be suitable as a binding agent in the formulation of metronidazole tablets with resultant tablets, of comparable physical and release properties to those of PVP and Acacia gum.

Keywords: Binder, metronidazole, tablet, cashew gum, acacia gum, polyvinyl pyrrolidone