The use of synthetic polymers as suspending agents is common in pharmaceutical formulations; however, their toxicity and environmental impact have raised safety and sustainability concerns. This has prompted the search for natural alternatives. This study investigated the suspending properties of purified Pentadesma butyracea gum in biphasic liquid formulations containing diffusible (chalk) and indiffusible (calamine) model solids. Suspensions were prepared using gum concentrations ranging from 1 to 5%w/v and compared with those formulated using tragacanth gum at equivalent concentrations. The suspensions were assessed for FTIR compatibility, pH, sedimentation rate, sedimentation volume, flow rate, apparent viscosity, flow behaviour and redispersibility cycles. Compatibility studies confirmed the absence of chemical interactions between P. butyracea gum, the active pharmaceutical ingredients and other excipients. Increasing the concentration of the Pentadesma butyracea gum produced a significant ( p < 0.05) decrease in pH (calamine: 6.75–6.12; chalk: 6.40–5.49), sedimentation volume (calamine: 47.5%–100%; chalk: 34.25%–51.25%), flow rate (calamine: 1.06–0.67 mL/s; chalk: 1.07–0.78 mL/s) and redispersibility cycles (calamine: ∼7–5; chalk: ∼3‐2), along with a significant increase ( p < 0.05) in the apparent viscosity of the suspensions (calamine: 0.025–0.033 Pas; chalk: 0.025–0.038 Pas). Also, there was a decrease in sedimentation rate with increasing Pentadesma butyracea concentration from 15 to 180 min. A similar trend was observed for the tragacanth gum–based suspensions. At concentrations ≥ 3%w/v, P. butyracea gum exhibited suspending performance compared to tragacanth, while maintaining acceptable pourability due to its shear‐thinning behaviour. These findings highlight the potential of Pentadesma butyracea gum as a safe, biodegradable and effective natural alternative to conventional suspending agents in pharmaceutical suspensions.
Archer et al. (Thu,) studied this question.