Evaluation of the suspending properties of Cola acuminata gum on calamine suspension
Many natural gums are employed as suspending agents in the formulation of pharmaceutical suspensions. The search to develop locally available natural gum from apparently a waste product as an alternative suspending agent stimulated the interest in this present study. Cola acuminata gum (CAG) extracted from Cola acuminata pods was subjected to some preliminary physicochemical and phytochemical evaluations. Calamine suspensions were formulated with CAG between the concentration range of 1 – 4 % w/v and compared with suspensions formulated with two standard suspending agents (tragacanth and acacia gums). Sedimentation volume, flow rate, rheology and redispersibility were used as evaluating parameters. Skin irritation test was carried out on albino rats using 5 % w/v aqueous dispersion of CAG and calamine suspension containing 4 % w/v of CAG to ascertain the gum’s suitability in the formulation of dermatological products. The results revealed that CAG is a hydrophillic polysaccharide gum containing mixture of monosaccharides and swells in water to produce viscous mucilage. At all concentrations employed, CAG possessed superior suspending properties relative to other gums. The suspending abilities of the gums are in the order of CAG > tragacanth > acacia. Comparatively, the performance of 1% w/v of CAG was similar to that of 3 % w/v of tragacanth gum. CAG is a potential alternative suspending agent in the preparation of pharmaceutical suspensions. The skin irritation test showed that CAG can be safely used in the formulation of dermatological products to be applied to the skin.
Keywords: Cola acuminata gum, suspending agent, dermatological suspension, skin irritation