Semi-solid topical formulations containing nimesulide-loaded nanocapsules showed in-vivo anti-inflammatory activity in chronic arthritis and fibrovascular tissue models.

Objective: To evaluate the anti-inflammatory activity of topical gel containing nimesulide-loaded nanocapsules using experimental models in vivo, and to compare the anti-inflammatory activity of two nimesulide preparations.

Materials: Male Wistar rats (200-250 g) treated with gel containing empty nanocapsules (GEN); gel containing nimesulide in the free form (GNFF) or gel containing nimesulide-loaded nanocapsules (GNN).

Methods: Nanoprecipitation methods were used to prepare the colloidal suspension. In-vivo experimental models of paw edema, acute and chronic arthritis, and granuloma formation were used. The gels were applied topically in all models.

Results: The nanocapsules had an average particle size of 344.6 nm ± 4.33 and a polydispersity index of 0.251 ± 0.002. The models of acute inflammation (paw edema and arthritis) showed that GNFF and GNN were able to inhibit the inflammatory process with similar efficacy. Moreover, nanoencapsulation significantly increased the anti-inflammatory activity of nimesulide in two chronic inflammation models (chronic arthritis and granuloma). The GNFF- and GNN-induced inhibition of inflammation in the chronic arthritis model were 27.75 and 81.5%, respectively. Similarly, GNFF and GNN reduced granuloma formation by 2.82 and 36.66%.

Conclusion: Nanoencapsulation increased the anti-inflammatory activity of topical nimesulide in chronic inflammation models.