Effect of oil phase kinds on preparation of monodisperse gelatin microbeads using microchannel emulsification

Abstract

The effect of the oil phase kinds has been investigated in the preparation of monodisperse gelatin microbeads using the microchannel (MC) emulsificatoion. Hexane, heptane, ethyl hexanoate, octanoic acid and triolein were used as continuous phases with 5wt% tetraglycerin condensed ricinoleic acid ester. Gelatin solution (5wt%) was used as disperse phase. The disperse phase was fed into the continuous phase through the MCs with MC equivalent diameter of 16.8μm at 40°C. Emulsion droplets were formed with average diameters of 38.7μm in hexane, 37.7μm in heptane and 36.8μm in ethyl hexanoate. Relative standard deviations were 3.5% in hexane, 4.5% in heptane and 3.4% in ethyl hexanoate, while the average diameter and relative standard deviation of the gelatin solution in triolein emulsion were 63.5μm and 20%. On the contrary, the continuous outflow of the disperse phase into octanoic acid system was observed. It was difficult to collect emulsion droplets in water-in-hexane systems. Therefore, the preparations of gelatin microbeads were performed only with water-in-heptane and water-in-ethyl hexanoate systems. Average diameters of microbeads formed in heptane and ethyl hxanoate systems were 18.2μm and 16.9μm, respectively. Relative standard deviations were 8.8% in heptane and 18% in ethyl hexanoate.