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A comparative study of roll compaction of free-flowing and cohesive pharmaceutical powders.
MedLine Citation:
PMID:  22402475     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Roll compaction is widely adopted as a dry granulation method in the pharmaceutical industry. The roll compaction behaviour of feed powders is primarily governed by two parameters: the maximum pressure and the nip angle. Although the maximum pressure can be measured directly using pressure sensors fitted in the rolls, it is not a trivial task to determine the nip angle, which is a measure of the size of the compaction zone and hence the degree of compression. Thus a robust approach based upon the calculation of the pressure gradient, which can be obtained directly from experiments using an instrumented roll compactor, was developed. It has been shown that the resulting nip angles are comparable to those using the methods reported in literature. Nevertheless, the proposed approach has distinctive advantages including (1) it is based on the intrinsic features of slip and no-slip interactions between the powder and roll surface and (2) it is not necessary to carry out wall friction measurements that involve walls that may not be representative of the roll compactor in terms of the surface topography and surface energy. The method was evaluated by investigating the effect of roll speed for two pharmaceutical excipients with distinctive material properties: microcrystalline cellulose (MCC) and di-calcium phosphate dihydrate (DCPD). It was found that the maximum pressure and nip angle for DCPD, which is a cohesive powder, decrease sharply with increasing roll speed whereas they are essentially independent of roll speed for MCC, which is an easy flowing powder. The roll compaction behaviour of MCC-DCPD mixtures with various compositions was also investigated in order to evaluate the effects of flowability. It was found that the nip angle and maximum pressure generally increased with improved flowability of the feed powders.
Authors:
Shen Yu; Bindhu Gururajan; Gavin Reynolds; Ron Roberts; Mike Adams; Chuan-Yu Wu
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-2-28
Journal Detail:
Title:  International journal of pharmaceutics     Volume:  -     ISSN:  1873-3476     ISO Abbreviation:  -     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-3-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7804127     Medline TA:  Int J Pharm     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012. Published by Elsevier B.V.
Affiliation:
School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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