In this research work, the designation of a new microemulsion formulation for the transdermal application of rutin was investigated. After the construction of pseudo-ternary phase diagrams containing tween 80 as a surfactant, ethylene glycol as co-surfactant and IPM (Isopropyl myristate) as the oil phase, the D-optimal mixture experimental design was used for the optimization process. The independent variables were oil, surfactant/co-surfactant and water weight concentrations and the two response variables were rutin solubility in microemulsions and drug release from microemulsions. After that, physicochemical characterization and stability studies were performed. In the other part the rutin, as an active pharmaceutics agent was loaded in the optimized microemulsion formulation to study kinetic of its release and sun protection factor. To investigate the exvivo skin permeation and retention of the drug from the carriers, the optimized formulation and its gel form, were examined on rat skin at similar conditions. The proposed formulation showed different release rate, skin permeation, sun protection factor and particle size, compared to recent works. Obtained results indicated that the microemulsion formulation can be used, especially in gel form, as an effective vehicle for prolong transdermal delivery of rutin desirably in sunscreen formulations.
