Celecoxib nanoemulsion: skin permeation mechanism and bioavailability assessment.

The aim of the present study was to assess the skin permeation mechanism and bioavailability of celecoxib (CXB) using novel nanoemulsion formulation. Fourier transform infrared spectra and differential scanning calorimetric thermogram of skin treated with nanoemulsion indicated that permeation occurred due to the extraction of stratum corneum (SC) lipids by nanoemulsion. The significant decrease in activation energy for CXB permeation across rat skin indicated that the SC lipid bilayers were significantly disrupted (p < 0.05). Photomicrograph of skin sample showed the disruption and extraction of lipid bilayers as distinct voids and empty spaces visible in the epidermal region. The absorption of CXB through transdermally applied nanoemulsion and nanoemulsion gel resulted in 3.03- and 2.65-fold increases in bioavailability when compared with conventional oral capsule formulation. Overall, these findings indicated that nanoemulsions can be successfully used for the enhancement of skin permeation and bioavailability of poorly soluble drugs.