Novel Capsaicin Nanogel for Arthritic Pain and Inflammation Management: Formulation, In Vitro, Ex-vivo and In Vivo...

The present work aimed to prepare and evaluate novel capsaicin (CAP) loaded nanosponges (NS) embedded Carbopol hydrogel (CAPNS-HG) with rosemary oil (RO) for arthritis management. CAP loaded NS were formulated using melt technique employing diphenylcarbonate and β-cyclodextrin. To facilitate their dermal application, CAPNS were integrated with Carbopol 934 hydrogel using RO as a permeation enhancer. Nanogel samples so formed were analyzed for physicochemical and rheological properties, followed by their in vitro, ex vivo, and in vivo evaluations. Based on the findings herein, CAPNS-HG was found to exhibit favorable rheological characteristics (610.56 cP), effective skin permeation (31.410 ± 1.145 µg/cm²), and delayed-release (61.91% in 24 h). Further, the hydrogel was observed to follow Korsmeyer-Peppas release kinetics with the Fickian diffusion mechanism. Outcomes of the in vitro irritation study demonstrated that CAPNS-HG significantly reduced skin irritation (four times; CAP-HG 12.159 ± 2.502 and CAPNS-HG 03.497 ± 0.096), which was also validated from in vivo evaluations. Further, a remarkable decrease in inflammation (20.869 ± 0.13%) was noted in FCA-induced arthritic animals. Improved hematological profile along with histological and X-ray data substantiated reduction in arthritic symptoms in CAPNS-HG treated animals. Hence, it can be concluded from the findings that CAPNS-HG is a safer and more promising delivery option for alleviating complete FCA-induced symptoms. The combination of CAPNS with hydrogel further augmented the therapeutic efficiency, resulting in a novel formulation for pain and inflammation management in this chronic disorder.