Formulation, Characterization and Evaluation of the in Vitro Skin Permeation of Nanostructured Lipid Carriers Encapsulated Tripterine

To develop and evaluate potential of nanostructured lipid carriers (NLCs) as a topical carrier for enhanced skin permeation of tripterine. Tripterine-loaded NLCs were prepared by solvent diffusion method. The concentrations of lipophilic and hydrophilic surfactants were optimized based on the size and the entrapment efficiency (EE) of the resulting NLC. An amorphous state in the NLC matrix and a spherical morphology were observed in the optimized tripterine-loaded NLCs by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The average drug entrapment efficiency(EE), particle size and zeta potential of the tripterine-loaded NLCs were determined by ultra filtration and laser particle size analyzer, which were (88.64±0.57) %, (132.3±25) nm and (-26.5±3.4) mV, respectively. Drug release profile of tripterine-loaded NLCs in vitro was in accordance with Ritger and Peppas equation (ln R = 0.6571 ln t-2.9074, r = 0.9951) with a delayed release of tripterine. Moreover, compared with tripterine solution, the tripterine-loaded NLCs improved drug deposition in the skin of rat significantly. Considering the cellular up taking rate, the concentrations of tripterine after incubated with NLCs was 1.6-fold increased compared with tripterine solution. The results of penetration experiment and cellular uptake indicated that NLCs could enhance the drug deposition. In conclusion, our results demonstrated that the NLCs system is a promising carrier for topical delivery of tripterine with improved drug deposition into skin.