Cissus stem gum as potential dispersant in pharmaceutical liquid systems 2: The emulsifying and suspending properties

The emulsifying and suspending properties of a new gum derived from the stem of cissus rufescence family Amphelidaceae were studied. Stability of the liquid paraffin emulsions prepared using this mucilaginous substance was compared with that containing tragacanth or acacia. The rate of globule coalescence was determined using Sherman's equation for concentrated emulsions. The suspending ability of the polymer was compared with that of tragacanth or compound tragacanth. The rate of deflocculation, K, was found to obey a power law equation: beta t = beta 0 e-kt in zinc oxide suspensions. At concentrations above 0.75% w/v, cissus gum produced liquid paraffin emulsion with minimal separation. The rate of globule coalescence was in the order acacia > cissus > tragacanth and rate of creaming was tragacanth > acacia > cissus. At concentrations of 0.6 to 1.0% w/v, cissus gum produced highly flocculated zinc oxide suspensions, which exhibited good redispersibility. Stability of the agglomerated, dispersed particles was similar to that produced using tagacanth mucilage.