Preparation of pH-sensitive particles by membrane contactor

In this work, pH-sensitive particles are synthesized using a membrane contactor technique. The polymer (Eudragit® L100 or Eudragit® E100) is dissolved in water at a set pH and is then passed through the pores of a membrane into a continuous phase of a different pH. Contact with the continuous phase causes the pH-sensitive polymer to precipitate. The final particle size distribution (PSD) using this membrane contactor technique is compared to that of a similar batch process. The influence of the different parameters of the process (pressure, cross-flow velocity, concentration of polymer and temperature) on the PSD are studied. The results allow analysis of the different forces controlling the formation of droplets at the membrane pores.