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The properties of HPMC: PEO extended release hydrophilic matrices and their response to ionic environments

Hu, Anran; Chen, Chen; Mantle, Michael D.; Wolf, Bettina; Gladden, Lynn F.; Rajabi-Siahboomi, Ali; Missaghi, Shahrzad; Mason, Laura; Melia, Colin D.


Anran Hu

Chen Chen

Michael D. Mantle

Bettina Wolf

Lynn F. Gladden

Ali Rajabi-Siahboomi

Shahrzad Missaghi

Laura Mason

Colin D. Melia



Investigate the extended release behaviour of compacts containing mixtures of hydrophilic HPMC and PEO in hydrating media of differing ionic strengths.

The extended release behaviour of various HPMC:PEO compacts was investigated using dissolution testing, confocal microscopy and magnetic resonance imaging, with respect to polymer ratio and ionic strength of the hydrating media.

Increasing HPMC content gave longer extended release times, but a greater sensitivity to high ionic dissolution environments. Increasing PEO content reduced this sensitivity. The addition of PEO to a predominantly HPMC matrix reduced release rate sensitivity to high ionic environments. Confocal microscopy of early gel layer development showed the two polymers appeared to contribute independently to gel layer structure whilst together forming a coherent and effective diffusion barrier. There was some evidence that poorly swollen HPMC particles added a tortuosity barrier to the gel layer in high ionic strength environments, resulting in prolonged extended release. MRI provides unique, non-invasive spatially resolved information from within the HPMC:PEO compacts that furthers our understanding of USP 1 and USP 4 dissolution data.

Confocal microscopy and MRI data show that combinations of HPMC and PEO have advantageous extended release properties, in comparison with matrices containing a single polymer.


Hu, A., Chen, C., Mantle, M. D., Wolf, B., Gladden, L. F., Rajabi-Siahboomi, A., …Melia, C. D. (2017). The properties of HPMC: PEO extended release hydrophilic matrices and their response to ionic environments. Pharmaceutical Research, 34(5), 941-956.

Journal Article Type Article
Acceptance Date Aug 25, 2016
Online Publication Date Sep 15, 2016
Publication Date May 1, 2017
Deposit Date May 30, 2017
Publicly Available Date May 30, 2017
Journal Pharmaceutical Research
Print ISSN 0724-8741
Electronic ISSN 1573-904X
Publisher American Association of Pharmaceutical Scientists
Peer Reviewed Peer Reviewed
Volume 34
Issue 5
Pages 941-956
Keywords confocal fluorescence microscopy; digital imaging; dissolution; HPMC; hydrophilic matrix; MRI; PEO; polymer mixtures
Public URL
Publisher URL
Additional Information The original publication is available at


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