PHARMACEUTICAL SUSPENSIONS

Background: The stability of pharmaceutical suspensions depends on their rheological properties, which are influenced by the type and concentration of suspending agents. This study evaluated and compared the rheological properties and performance of various suspending agents in ibuprofen suspension formulations. Methodology: Ten suspending agents Chitosan, Sodium Alginate, NaCMC, HPMC, HEC, Carbopol, CMEC, MC, Eudragit L-100, and PVP, were prepared using appropriate solvents. Eudragit L-100 was dissolved in ethanol, HEC, HPMC, and Carbopol in hot water, Chitosan in 1% H₂SO₄, while others were dispersed in distilled water. Each was evaluated for pH,
density, and viscosity. Six agents (NaCMC, CMEC, Sodium Alginate, MC, HPMC, and Carbopol) were selected to formulate ibuprofen suspensions, assessed for pH, viscosity, and sedimentation rate at ambient temperature. Results: All suspending agents produced formulations with acceptable pH (4.1–5.9). Viscosity increased with polymer concentration; Carbopol and NaCMC at 1.0% formed gel like systems, while0.5%gave smooth, pourable suspensions. Sedimentation tests showed the control settled rapidly, whereas Carbopol and NaCMC formulations exhibited the highest stability with uniform sedimentation over seven days. Conclusion: All agents improved suspension stability, though performance varied with concentration. Carbopol and NaCMC at 0.5% provided the best balance between viscosity and pourability, making them most suitable for ibuprofen suspensions