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dc.contributor.authorParadkar, Anant R*
dc.contributor.authorKelly, Adrian L.*
dc.contributor.authorCoates, Philip D.*
dc.contributor.authorYork, Peter*
dc.date.accessioned2014-04-28T11:05:02Z
dc.date.available2014-04-28T11:05:02Z
dc.date.issued2009
dc.identifier.citationParadkar AR, Kelly AL, Coates PD et al (2009) Shear and extensional rheology of hydroxypropyl cellulose melt using capillary rheometry. Journal of Pharmaceutical and Biomedical Analysis. 49(2): 304-310.
dc.identifier.urihttp://hdl.handle.net/10454/6121
dc.descriptionNo
dc.description.abstractWith increasing interest in hot melt extrusion for preparing polymer-drug systems, knowledge of the shear and extensional rheology of polymers is required for the formulation and process design. Shear and extensional rheology of three commercial grades of hydroxypropyl cellulose (HPC) was examined at 140, 145 and 150 degrees C using twin bore capillary rheometry at range of processing rates. The power law model fitted for shear flow behaviour up to shear strain rates of approximately 1000s(-1), above which measured shear viscosities deviated from the power law and surface instabilities were observed in the extrudate, particularly for higher molecular weight grades. Shear thinning index was found to be relatively independent of temperature and molecular weight, whilst the consistency index, indicative of zero shear viscosity increased exponentially with increase in molecular weight. Extensional viscosity of all grades studied was found to decrease with increasing temperature and increasing processing rate. Foaming of the extrudate occurred especially at low temperatures and with the high molecular weight grade. An understanding of the relationships between shear and extensional flows with temperature, processing rate and molecular weight is a useful tool for process design; optimisation and troubleshooting of Hot melt extrusion (HME) of pharmaceutical formulations.
dc.subjectCellulose analogs
dc.subjectPharmaceutical chemistry
dc.subjectMaterials testing methods
dc.subjectMolecular weight
dc.subjectPolymers
dc.subjectPowders
dc.subjectRheology
dc.subjectShear strength
dc.subjectPharmaceutical technology
dc.subjectTemperature
dc.subjectViscosity
dc.subjectREF 2014
dc.titleShear and extensional rheology of hydroxypropyl cellulose melt using capillary rheometry
dc.status.refereedYes
dc.typeArticle
dc.type.versionNo full-text in the repository
dc.identifier.doihttps://doi.org/10.1016/j.jpba.2008.11.014


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