Spray Drying
Aliquots of the double emulsion, consisting of dry mass ratios of 1 part PLGA and 3.3 parts PVA or P-407, were either directly spray dried or spiked with 9 parts matrix excipient. The aliquots were fed at 2 mL/min into a ProCepT 4M8-TriX lab scale spray dryer equipped with a straight and a conical drying column and a small cyclone (ProCepT nv; Zelzate, Belgium); atomized with a 1.0 mm bi-fluid nozzle and 10 L/min nitrogen; and dried at 80°C inlet drying air temperature, 0.4 m3/min drying air flow, 40–42°C cyclone outlet temperature, and a pressure drop of 60–65 mbar over the cyclone. Ambient conditions were between 20 and 23°C and 40–60% rh.