Preparation of phospholipid oil-in-water microspheres by microchannel emulsification technique

A novel microchannel (MC) emulsification technique for producing super-monodisperse microspheres (MS) was recently proposed. In this study, we investigated the formation of monodisperse oil-in-water (O/W)-MS using lecithin and lysophosphatidylcholine (LPC) as surfactant by applying the MC emulsification technique. When we used lecithin to produce O/W-MS, we observed coalescence of the formed MS and the continuous outflow of the oil phase through the MC. This was probably due to the insufficient interfacial activity of lecithin and the subsequent wetting of the MC surface by the oil phase during the emulsification process. The monodisperse O/W-MS could not be produced when lecithin was used as the only surfactant. However, we successfully produced monodisperse O/W-MS by using hydrophilic LPC dissolved in the water phase. Also, a more stable emulsification process producing monodisperse O/W-MS was found using lecithin in the oil phase and LPC in the water phase. The monodisperse O/W-MS production was improved by a special surface oxidation treatment of the MC plate.