Microparticles Based on Chitosan/Xanthan Gum Polyelectrolyte Complex Modulate the Anti-Inflammatory and Antinociceptive Effects of Ibuprofen and Escin

Polyelectrolyte complex (PEC)-based carriers offer a promising strategy to improve the oral delivery of anti-inflammatory agents with limited bioavailability or variable pharmacodynamic profiles. This study evaluated the anti-inflammatory and antinociceptive effects of previously optimized formulations of chitosan/xanthan gum PEC microparticles loaded with either ibuprofen or escin, using the carrageenan-induced paw edema model, histopathological and cyclooxygenase-2 (COX-2) immunohistochemical analyses, and the hot plate test. Ibuprofen-loaded microparticles significantly reduced paw swelling during the peak inflammatory phase (5–6 h after treatment administration), although no significant differences in overall edema response or antinociceptive activity were observed compared with free ibuprofen. In contrast, escin-loaded microparticles at 10 mg/kg produced the most pronounced anti-inflammatory effect, significantly reducing paw swelling, edema area under the curve (AUC), histopathological lesion scores, and COX-2 expression compared with both the negative control and the corresponding free escin formulation. Escin-loaded microparticles also showed stronger and more sustained antinociceptive activity than free escin. However, the 20 mg/kg formulation did not provide additional anti-inflammatory or antinociceptive benefits. These findings demonstrate that chitosan/xanthan gum PEC microparticles can enhance the pharmacodynamic performance of orally administered anti-inflammatory agents. The magnitude of this effect depended on the incorporated drug and was particularly notable for escin, for which microencapsulation improved both anti-inflammatory and antinociceptive efficacy.