Granule size control and targeting in pulsed spray fluid bed granulation.
The primary aim of the study was to investigate the effects of pulsed liquid feed on granule size. The secondary aim was to increase knowledge of this technique in granule size targeting. Pulsed liquid feed refers to the pump changing between on- and off-positions in sequences, called duty cycles. One duty cycle consists of one on- and off-period. The study was performed with a laboratory-scale top-spray fluid bed granulator with duty cycle length and atomization pressure as studied variables. The liquid feed rate, amount and inlet air temperature were constant. The granules were small, indicating that the powder has only undergone ordered mixing, nucleation and early growth. The effect of atomizing pressure on granule size depends on inlet air relative humidity, with premature binder evaporation as a reason. The duty cycle length was of critical importance to the end product attributes, by defining the extent of intermittent drying and rewetting. By varying only the duty cycle length, it was possible to control granule nucleation and growth, with a wider granule size target range in increased relative humidity. The present study confirms that pulsed liquid feed in fluid bed granulation is a useful tool in end product particle size targeting.
Division of Pharmaceutical Technology, Faculty of Pharmacy, University of Helsinki, PO Box 56 (Viikinkaari 5 E), FI-00014 Helsinki, Finland. henrik.ehlers@helsinki.fi
Henrik
H
Ehlers
Anchang
A
Liu
Heikki
H
Räikkönen
Juha
J
Hatara
Osmo
O
Antikainen
Sari
S
Airaksinen
Jyrki
J
Heinämäki
Honxiang
H
Lou
Jouko
J
Yliruusi
D002110:Caffeine / Q000032:analysis; D016503:Drug Delivery Systems / Q000379:methods*; D006813:Humidity; D007785:Lactose / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D055585:Physical Phenomena; D011208:Powders / Q000032:analysis*; D013678:Technology, Pharmaceutical / Q000379:methods
D011208:Powders; D002110:Caffeine; D007785:Lactose