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

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. 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). 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. The nanocapsules had an average particle size of 344.6 nm +/- A 4.33 and a polydispersity index of 0.251 +/- A 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%. Nanoencapsulation increased the anti-inflammatory activity of topical nimesulide in chronic inflammation models.