Bicelles are smaller than liposomes and are expected to show greater efficiency for transdermal drug delivery. Formulating bicelles with low-cost materials and avoiding complicated formulation processes would extend their application fields. In this study, lecithin and poly(oxyethylene) sorbitan monooleate (Tween80) were dissolved in 1,3-butanediol, and the mixture was then dispersed in water by ultrasonication. Using this semi spontaneous method, we obtained bicelles that were stable for up to 180 days.