Evaluating Natural Suspending Agents in Pharmaceutical Suspensions: A Comparative Analysis

Introduction: Mucilage-rich natural substances have attracted interest as plant-based suspending agents (SAs) due to their ability to form colloidal gels and stabilize pharmaceutical suspensions. This study evaluates the effectiveness of novel herbal excipients in paracetamol suspensions compared to conventional SAs to enhance the stability of oral formulations for poorly soluble drugs. Methods: Optimal SA concentrations were determined based on viscosity, pH, flow rate, and sedimentation volume. Seven formulations (F1–F7) were prepared using acacia, tragacanth, marshmallow, carbopol 980, chitosan, kaolin, and sodium CMC, respectively, and assessed for key physicochemical parameters. Comparative dissolution testing in 0.1N HCl and phosphate buffer (pH 6.8), stability studies on F3, F4, F6, and a marketed formulation, and statistical analysis (two-way ANOVA with Bonferroni post-test) were conducted. In vivo antipyretic activity was also evaluated. Results: F4 and F6 exhibited superior suspending properties, including high viscosity, ideal sedimentation volume, and microbial stability. F3 showed moderate performance with fungal growth over time. Drug release was higher in 0.1N HCl (66.91–101.62%) than in phosphate buffer. All formulations showed antipyretic activity. No significant difference was found compared to a marketed product (p <0.05). Discussion: An optimization study determined the optimal SA concentration based on parameters like viscosity, pH, flow rate, and sedimentation volume. Suspensions (F1-F7) containing acacia, tragacanth, marshmallow, carbopol 980, chitosan, kaolin, and sodium CMC were formulated and evaluated for viscosity, density, sedimentation volume, dispersibility, and pH. Comparative dissolution analysis in 0.1N HCl and phosphate buffer (pH 6.8) and stability testing of F3, F4, F6, and a marketed preparation were conducted, with statistical analysis using 2-way ANOVA and Bonferroni Post Test along-with in-vivo antipyretic activity. Conclusion: Overall, Carbopol 980 and Sodium CMC are recommended for stable suspension formulations, while marshmallow warrants further investigation as a natural alternative in combination systems.