The role of emulsion parameters in tramadol sustained-release from electrospun mats

Tramadol is an analgesic usually prescribed for the management of pain, with a certain risk of addiction in chronic patients. The incorporation of tramadol in sustained-release systems results particularly attractive for the administration of accurate doses. In this work, emulsion electrospinning was used for the preparation of tramadol-loaded nanofibrous membranes based on poly(ε-caprolactone). Compositional and processing parameters were screened and evaluated in terms of the morphology of the resulting nanofibers, encapsulation efficiency and drug release in time. The polymer concentration, surfactant type and amount, and the homogenization rate used for the emulsions preparation were found to greatly affect the fluid stability and the resulting materials structure and functionality. The intrinsic features of the starting fluid studied in this work played a significant role for the modulation of tramadol release from nanofibrous matrices. The use of sodium dodecyl sulfate as surfactant with an optimal homogenization rate allowed the preparation of electrospun fibrous membranes with good encapsulation efficiency, a minimal burst release and a sustained delivery of tramadol in time.