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Knowing about crystal formation of organic compounds is knowing about pathways to improve a patient’s life. The crystal shape and size impact several drug aspects such as flowability, compatibility, and dissolution. A controlled solution mixing and antisolvent mass transfer is key to obtain desired crystal properties, which can be achieved using membrane technology. A membrane plays the role of a physical barrier between the antisolvent and the crystallizing solution, which then controls the dosage of the antisolvent into the crystallizing solution. This control of antisolvent addition avoids the formation of local supersaturations; meaning, focal points where the concentration of antisolvent is high compared to the rest of the bulk solution, hence having greater nucleation (or birth of crystals). I this study, glycine-ethanol-water was used as the model crystallization system and porous polymeric membranes of various properties were used to evaluate the role of membrane porosity, hydrophobicity, thickness, and surface morphology on crystal development. Results show that a tradeoff between the membrane properties and the operating conditions is necessary for an optimum operation of membrane-assisted antisolvent crystallization (MAAC). The thinner was the membrane, the more hydrophobic or the more porous it was, the higher was the antisolvent transmembrane flux, the lower was the induction time and the smaller were the resulting crystals. Besides, the surface patterned membranes gave overall a larger crystal size, and a more uniform crystal size distribution. The use of MAAC eventually has several advantages, it can easily be scaled-up, it is …