Characterization of cephalexin loaded nonionic microemulsions

► U-type newly formulated biocompatible microemulsions enhance the solubilization of cephalexin. ► Electrical conductivity, dynamic light scattering, ultrasonic velocity and EPR spectroscopy methods were applied. ► Cephalexin solubilization capacity is microstructure dependent and remains solubilized at the interface upon dilution. ► These formulations can be progressively and fully diluted by aqueous phase.