Evalution Of The Emulsifying Potential Of Shea Tree Gum

Abstract

The emulsifying potential of shea tree gum in pharmaceutical emulsions was investigated. This was done by formulating emulsions with different types of oils using the wet and dry gum methods. The ratio of oil to water to gum needed for the preparation of stable primary emulsions was determined. All the primary emulsions formulated creamed readily on dilution. The stability of paraffin oil emulsions was assessed and reduction in creaming was attempted through homogenization, addition of a surfactant and a thickening agent. Addition of a small quantity of Tween 60 (0.001– 0.002% w/v) which is very close to the critical micelle concentration of the surfactant stabilised the emulsions. Homogenisation and addition of xanthan gum, a thickening agent, had no marked stabilising effect. The degree of stability of the stable emulsions was also investigated by centrifugation using the emulsion stability factor ‘S’ which gave a 100% emulsion stability indicating a very stable emulsion when stabilized with 0.002% w/v Tween 60. In addition, the apparent viscosities determined for the emulsions showed that there was no change in viscosity or turbidity during the 12 w observations. Also the size index, R, values were found to be within the range of 0.27 -0.29 which indicate that the emulsions were stable and the size of the droplets were relatively small. At the same concentration, the shea gum was found to produce more stable emulsions with ‘R’ values less than that of acacia gum (0.37-0.38) at the same concentration.