Effect of the manufacturing conditions on the structure and permeability of polymer films intended for coating undergoing phase separation

Marucci, Mariagrazia; Arnehed, Johan; Jarke, Annica; Matic, Hanna; Nicholas, Mark; Boissier, Catherine; Corswant, Christian von

doi:10.1016/j.ejpb.2012.09.020

Cited by 22 publications

(27 citation statements)

References 18 publications

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“…These two characteristics can be studied by analyzing the number, location and connection of the pore branching points, where at least three pore channels meet. For example, the more branching points there are that the pore structure in EC/HPC blended films can be inhomogeneous and 20 anisotropic (Häbel et al, 2016;Marucci et al, 2013). In this work, we find statistical evidence for the inhomogeneity and anisotropy by describing the pore structure in terms of its branching points and by using methods from point process theory.…”

Section: Introductionmentioning

confidence: 59%

“…Since several coating layers are sprayed on top of each other, the lower layers are re-wetted more often than upper layers. Consequently and due to a small increase in temperature at the end of the spraying process, phase separation occurs to a lower extent in the upper 115 layers resulting in smaller domains towards the air-side of the film compared to the drum-side (Gebäck et al, 2015;Marucci et al, 2013). As the interfacial free energy is minimized during phase separation, new HPC drops are more likely to coalesce with large HPC domains than smaller ones.…”

mentioning

confidence: 99%

“…The process is frozen by a high film viscosity which is reached at a certain solvent concentration (Marucci et al, 2013). Since several coating layers are sprayed on top of each other, the lower layers are re-wetted more often than upper layers.…”

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confidence: 99%

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A three-dimensional anisotropic point process characterization for pharmaceutical coatings

et al. 2017

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Spatial characterization and modeling of the structure of a material may provide valuable knowledge on its properties and function. Especially, for a drug formulation coated with a polymer film, understanding the relationship between pore structure and drug release properties is important to optimize the coating film design. Here, we use methods from image analysis and spatial statistics to characterize and model the pore structure in pharmaceutical coatings. More precisely, we use and develop point process theory to characterize the branching structure of a polymer blended film with data from confocal laser scanning microscopy. Point patterns, extracted by identifying branching points of pore channels, are both inhomogeneous and anisotropic. Therefore, we introduce a directional version of the inhomogeneous K-function to study the anisotropy and then suggest two alternative ways to model the anisotropic * Corresponding author Email address: henrike.habel@chalmers.se (Henrike Häbel)Preprint submitted to Spatial Statistics October 10, 2017 three-dimensional branching point structure. First, we apply a linear transformation to the data such that it appears isotropic and subsequently fit isotropic inhomogeneous Strauss or Lennard-Jones models to the transformed pattern.Second, we include the anisotropy directly in a Lennard-Jones and a more flexible step-function model with anisotropic pair-potential functions. The methods presented here will be useful for anisotropic inhomogeneous point patterns in general and for characterizing pharmaceutical coatings or other porous material in particular.

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Section: Introductionmentioning

confidence: 59%

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confidence: 99%

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A three-dimensional anisotropic point process characterization for pharmaceutical coatings

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“…The EC/HPC material has previously been studied experimentally in Marucci et al . (, ); Andersson et al . () and characterized statistically in Häbel et al .…”

Section: Methodsmentioning

confidence: 98%

A three‐dimensional statistical model for imaged microstructures of porous polymer films

Barman

Bolin

2017

Journal of Microscopy

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A thresholded Gaussian random field model is developed for the microstructure of porous materials. Defining the random field as a solution to stochastic partial differential equation allows for flexible modelling of nonstationarities in the material and facilitates computationally efficient methods for simulation and model fitting. A Markov Chain Monte Carlo algorithm is developed and used to fit the model to three-dimensional confocal laser scanning microscopy images. The methods are applied to study a porous ethylcellulose/hydroxypropylcellulose polymer blend that is used as a coating to control drug release from pharmaceutical tablets. The aim is to investigate how mass transport through the material depends on the microstructure. We derive a number of goodness-of-fit measures based on numerically calculated diffusion through the material. These are used in combination with measures that characterize the geometry of the pore structure to assess model fit. The model is found to fit stationary parts of the material well.

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“…2), which may be attributed to higher EC concentrations (8.9% w/w) in the coating solution. Generally, phase separation between EC and the pore former (HPC or MS) occurs during film drying process, and subsequently, EC-and HPC-or drug-rich domains are formed (42). The higher the EC concentration, the longer time it takes to lock the film structure and the rougher the surface of the obtained pellets eventually is.…”

Section: Effect Of Pore Former Types On Coating Process (Hpc Vs Ms)mentioning

confidence: 99%

Model Drug as Pore Former for Controlled Release of Water-Soluble Metoprolol Succinate from Ethylcellulose-Coated Pellets Without Lag Phase: Opportunities and Challenges

Wang¹,

Dai²,

Chang

et al. 2014

AAPS PharmSciTech

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Abstract. The objective of the present study was to evaluate the feasibility of using model drug metoprolol succinate (MS) as a pore former to modify the initial lag phase (i.e., a slow or non-release phase in the first 1-2 h) associated with the drug release from coated pellets. MS-layered cores with high drug-layering efficiency (97% w/w) were first prepared by spraying a highly concentrated drug aqueous solution (60% w/w, 70°C) on non-pareils without using other binders. The presence of MS in ethylcellulose (EC) coating solution significantly improved the coating process by reducing pellets sticking, which often occurs during organic coating. There may be a maximum physical compatibility of MS with EC, and the physical state of the drug in the functional coating layer of EC/MS (80:20) was simultaneously crystalline and noncrystalline (amorphous or solid molecule solution). The lag phase associated with hydroxypropylcellulose (HPC) as a pore former was not observed when MS was used as a pore former. The drug release from EC/ MS-coated pellets was pH independent, inversely proportional to the coating levels, and directly related to the pore former levels. The functional coating layer with MS as a pore former was not completely stabilized without curing. Curing at 60°C for 1 day could substantially improve the stability of EC/MScoated pellets. The physical state of the drug in the free film of EC/MS (85:15) changed partially from amorphous to crystal when cured at 60°C for 1 day, which should be attributed to the incompatibility of the drug with EC.

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Effect of the manufacturing conditions on the structure and permeability of polymer films intended for coating undergoing phase separation

Cited by 22 publications

References 18 publications

A three-dimensional anisotropic point process characterization for pharmaceutical coatings

A three-dimensional anisotropic point process characterization for pharmaceutical coatings

A three‐dimensional statistical model for imaged microstructures of porous polymer films

Model Drug as Pore Former for Controlled Release of Water-Soluble Metoprolol Succinate from Ethylcellulose-Coated Pellets Without Lag Phase: Opportunities and Challenges

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