Designing HPMC matrices with improved resistance to dissolved sugar

Williams, Hywel David; Ward, Robert W.; Culy, Anna; Hardy, Ian C.W.; Melia, Colin D.

doi:10.1016/j.ijpharm.2010.09.009

Cited by 21 publications

(15 citation statements)

References 24 publications

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“…[11][12]29,40 Figure 2 shows CLSM images of early gel layer formation in matrices undergoing hydration in water, full-fat milk, Intralipid R Images of matrices hydrating in water and the various fat emulsions appear to be very different (Fig. 2) and the examples shown in Figure 3 (t = 5 min) have been extracted to illustrate these in detail.…”

Section: Early Gel Layer Formation In Milk and Fat Emulsionsmentioning

confidence: 99%

“…12 The same formulation had been previously used in studies of the effects of dissolved sugars and salts. 12,29 Confocal laser scanning microscopy (CLSM) and magnetic resonance imaging (MRI) were used to explore the microscopic and macroscopic effects of interaction between fat emulsions and the rate-controlling surface "gel" layer of the hydrating matrix. Furthermore, two different USP dissolution test apparatus were used to explore the effects of hydrodynamics on matrix drug release behaviour.…”

Section: Introductionmentioning

confidence: 99%

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Drug release from HPMC matrices in milk and fat‐rich emulsions

Williams

Nott

Barrett

et al. 2011

Journal of Pharmaceutical Sciences

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Section: Early Gel Layer Formation In Milk and Fat Emulsionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Drug release from HPMC matrices in milk and fat‐rich emulsions

Williams

Nott

Barrett

et al. 2011

Journal of Pharmaceutical Sciences

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“…This suggests that the poorly hydrated HPMC might add a tortuosity factor to the diffusional release of drug through the gel layer, acting in a similar way to insoluble inclusions such as microcrystalline cellulose [43]. This might account for the slower release profiles of mixed matrices seen in the dissolution tests (figure 4 C).…”

Section: Early Gel Layer Development In Sodium Chloride Solutionsmentioning

confidence: 97%

The Properties of HPMC:PEO Extended Release Hydrophilic Matrices and their Response to Ionic Environments

Hu¹,

Chen

Mantle

et al. 2016

Pharm Res

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Abbreviations: Hydroxypropyl methylcellulose (HPMC), polyethylene oxide (PEO), Magnetic resonance imaging (MRI). Abstract PurposeInvestigate the extended release behaviour of compacts containing mixtures of hydrophilic HPMC and PEO in hydrating media of differing ionic strengths. MethodsThe 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. ResultsIncreasing 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. ConclusionsConfocal microscopy and MRI data show that combinations of HPMC and PEO have advantageous extended release properties, in comparison with matrices containing a single polymer.

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“…This behavior has been ascribed to the microcrystalline cellulose water insolubility that provides an additional barrier by increasing the tortuosity of the diffusion path, reducing the drug release rate. The microcrystalline cellulose content of EasyTab is 96.5% [22][23]. Table 1 summarizes the calculated regression parameters for the release profiles of metronidazole from tablets containing a fixed proportion of Noveon AA1 (20%) and varying proportions of metronidazole and EasyTab.…”

Section: Experimental Points and Calculated Regressionsmentioning

confidence: 99%

Influence of Free-Flow Excipients on Functional Performance of Noveonaa1 in Controlled-Release Tablets

Islas

Robles

2016

Int J Pharm Pharm Sci

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Objective: The aim of this work is the assessment of an eventual improvement in flowability of free flowing excipients on formulations containing Noveon AA1 and their influence on compactibility and release profile. Methods:Mixtures containing 20% Noveon AA1 and variable proportions of metronidazole and the free flowing excipients Prosolv EasyTab and GalenIQ 720 and 721were tested in their powder flow rate and the tablets compactibility and released profiles. Results:The powder flowability obtained with GalenIQ is about 20% better than that obtained with EasyTab. However, it is lesser than that considered as acceptable for a high-speed tableting machine. EasyTab reduces the drug release up to a half along with a continuing flattening of the release profile. This is attributed to an increasing tortuosity of the drug release path as the proportion EasyTab increases. GalenIQ restricts drug release in about a third with a lesser change in the release mechanism. This is attributed to competition for the available water inside the tablet, between the hydrating Noveon AA1 and the dissolving GalenIQ. The compactibility of the metronidazole/Noveon AA1 mixtures increases after addition of EasyTab in about 3.5 N per unit percentage of the added excipient while GalenIQ does it in about 2.6 N. Conclusion:The powder flowability of mixtures of metronidazole with Noveon AA1 was not suited for direct compression after addition of 40% of the free-flow excipient. The free-flow excipients reduce the metronidazole release rate and increase its compactibility. It was not observed a different clear functioning between both types of GalenIQ.

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Designing HPMC matrices with improved resistance to dissolved sugar

Cited by 21 publications

References 24 publications

Drug release from HPMC matrices in milk and fat‐rich emulsions

Drug release from HPMC matrices in milk and fat‐rich emulsions

The Properties of HPMC:PEO Extended Release Hydrophilic Matrices and their Response to Ionic Environments

Influence of Free-Flow Excipients on Functional Performance of Noveonaa1 in Controlled-Release Tablets

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