Study on the transdermal penetration mechanism of ibuprofen nanoemulsions

Objective: The purpose of this study was to research the mechanism of percutaneous penetration of Ibuprofen (IBU) nanoemulsion.Method: Transdermal penetration mechanism of IBU nanoemulsion was investigated by using Fourier transform infra-red spectral analysis (FTIR), differential scanning calorimeter thermogram (DSC), and activation energy (Ea) measurement. The in vivo skin penetration test of rats was carried out using Rhodamine B nanoemulsion to simulate the process of drug penetration into the skin, and the frozen section of the skin was observed by confocal laser scanning microscopy (CLSM).Result: FTIR spectra and DSC thermogram of rat skin treated with IBU nanoemulsion showed that infiltration occurred due to disruption of the stratum corneum (SC) protein–lipid structure and increasing of fluidity, hydration, and disruption of the lipid bilayer structure of the SC. The significant reduce in Ea (1.255 kcal/mol) for IBU permeating rat skin suggested crucial disruption of the SC lipid bilayers (P < 0.05), which is speculated that nanoemulsion may create new pathways to promote drug penetration. CLSM revealed that Rhodamine B penetrated into the SC in a shorter period of time and it accumulated around the sebaceous glands.Conclusion: The study of skin penetration mechanism indicated that nanoemulsion can be perfectly well used as the transdermal penetration of poorly soluble drugs.