PMID- 21742021
OWN - NLM
STAT- MEDLINE
DCOM- 20111227
LR  - 20161125
IS  - 1873-3476 (Electronic)
IS  - 0378-5173 (Linking)
VI  - 416
IP  - 1
DP  - 2011 Sep 15
TI  - A comparison of ram extrusion by single-holed and multi-holed dies for 
      extrusion-spheronisation of microcrystalline-based pastes.
PG  - 210-22
LID - 10.1016/j.ijpharm.2011.06.043 [doi]
AB  - The use of multi-holed dies as an alternative to single-holed dies for generating 
      extrudates for spheronisation was investigated both in terms of extrusion and 
      spheronisation performance. A model 45wt% microcrystalline cellulose (MCC)/water 
      paste was employed in ram extrusion tests with square-ended dies with 1, 6, 33 
      and 137 holes, all of diameter 1mm and length 2mm. The extrudates generated using 
      the multi-holed dies yielded pellets with comparable sphericity to those using 
      the single-holed die. Multi-holed dies could also be operated with lower paste 
      flow rates before encountering liquid phase migration (LPM). The characteristic 
      processing velocity for the onset of LPM was determined for each die 
      configuration and supported the hypothesis that LPM was caused by suction 
      effects. A simple model of the flow pattern in a lab-scale Fuji-Paudal frontal 
      screen extruder is presented which yields estimates of velocities and shear rates 
      involved in these devices. The pressure required to extrude the paste through 
      multi-holed dies was compared with the model proposed by Benbow and co-workers. 
      The paste rheology was characterised using the Benbow-Bridgwater approach, 
      employing 1, 2 and 3mm diameter dies of various lengths. The Benbow et al. model 
      under-predicted the observed extrusion pressure, which was attributed to its 
      failure to account for the redundant work contribution in these complex flows.
CI  - Copyright (c) 2011 Elsevier B.V. All rights reserved.
FAU - Zhang, M
AU  - Zhang M
AD  - Department of Chemical Engineering and Biotechnology, New Museums Site, Pembroke 
      Street, Cambridge CB2 3RA, UK.
FAU - Rough, S L
AU  - Rough SL
FAU - Ward, R
AU  - Ward R
FAU - Seiler, C
AU  - Seiler C
FAU - Wilson, D I
AU  - Wilson DI
LA  - eng
PT  - Comparative Study
PT  - Journal Article
DEP - 20110630
PL  - Netherlands
TA  - Int J Pharm
JT  - International journal of pharmaceutics
JID - 7804127
RN  - 0 (Drug Implants)
RN  - 0 (Ointments)
RN  - 9004-34-6 (Cellulose)
RN  - OP1R32D61U (microcrystalline cellulose)
SB  - IM
MH  - Cellulose/*chemistry
MH  - Drug Compounding/*instrumentation/methods/statistics & numerical data
MH  - Drug Implants/*chemistry
MH  - Ointments/*chemistry
MH  - Phase Transition
MH  - Pressure
MH  - Rheology
MH  - Shear Strength
EDAT- 2011/07/12 06:00
MHDA- 2011/12/28 06:00
CRDT- 2011/07/12 06:00
PHST- 2011/04/15 00:00 [received]
PHST- 2011/06/20 00:00 [revised]
PHST- 2011/06/24 00:00 [accepted]
PHST- 2011/07/12 06:00 [entrez]
PHST- 2011/07/12 06:00 [pubmed]
PHST- 2011/12/28 06:00 [medline]
AID - S0378-5173(11)00596-5 [pii]
AID - 10.1016/j.ijpharm.2011.06.043 [doi]
PST - ppublish
SO  - Int J Pharm. 2011 Sep 15;416(1):210-22. doi: 10.1016/j.ijpharm.2011.06.043. Epub 
      2011 Jun 30.