Abstract
Drug delivery systems are used to protect unstable pharmaceutical active substances, to modify the characteristics of the loaded drug or to deliver the active ingredient to its specific receptor. In this study, polyurethane-based particles were obtained and the influence of stirring speed during the synthesis, the drying speed of products as well as the chain extender/polyol ratio were determined in order to describe the characteristics of the new particles. The final particles were elongated in shape and stable up to 280oC. We established that the drying speed did not influence in a noticeable manner the particles size and led to the formation of a dispersed system in which the constituents presented a high tendency to form clusters or conglomerates. The results suggested that the stirring speed during the synthesis and the chain extender/polyol ratio may be used as two important parameters which can influence the particles sizes without affecting other characteristics. In vivo evaluation on mice skin model did not reveal any damaging properties of the newly synthesized particles.
Keywords: drug delivery system; polyurethane; zeta potential; skin irritation