Abstract
This study explains the development and characterization of microemulsions for iontophoretic drug delivery. The microemulsions were developed using a pseudo ternary phase diagram. Biphasic formulations of sesame oil were developed using a mixture of span 80 and tween 80 as surfactant mixture (S-mix). The composition of the Smix, sesame oil and water was varied. Microemulsions were formed at a Smix concentration of > 60 %. The formulations were characterized by microscopic studies, FTIR spectroscopy, viscosity, mechanical analysis and impedance analysis. A model drug, metronidazole, was incorporated in the microemulsions to check its drug release behavior. FTIR spectra suggested no interactions amongst the formulation components and the drug. The viscosity and firmness was higher in the microemulsion possessing lower water/surfactant ratio. The microemulsions were electroconductive in nature. The microemulsions showed 42-47 % increase in the amount of metronidazole released under the influence of current as compared to the passive release. The release profile followed zero order release kinetics. The developed microemulsions can be used for iontophoretic drug delivery applications.