The success of the double emulsification process and the size of the resulting APCN capsules depended on the diameters of the injection and collection capillary openings, the distance between the tip of the capillaries, and the flow rates of the three phases. The distance between the capillaries was 150 µm and the diameter of the inner capillary and the collector were set to 100 and 350 µm, respectively. The flow rates were optimized for the given distance between capillaries to obtain double emulsion microcapsules, as examined by microscopy. The flow rate of the outer phase varied in the range 50 -80 mL h -1 , the flow rate of the middle phase varied between 4 -6 mL h -1 , and the flow rate of the inner phase was set to values between 2.5 -3 mL h -1 . It was not possible to form double emulsions if the inner capillary and collector were too close or if the speed of the middle and inner phases were in the same order of magnitude.