Analysis of Case II drug transport with radial and axial release from cylinders

Kosmidis, Kosmas; Rinaki, Eleni; Argyrakis, Panos; Macheras, Panos

doi:10.1016/s0378-5173(03)00030-9

Cited by 71 publications

(41 citation statements)

References 8 publications

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“…Equally, other experimental studies have reported cases of spheres with initial occlusions much larger than the Stokes-Einstein diameter of the microencapsulated molecule [3,13]. Nevertheless, as long as the proteins undergo very restricted diffusion through pores, it is appropriate to treat diffusion by individual random walks of a given number of agents [21,22]. In such cases, multi-agent systems seem reasonable approximations for a "protein -PLGA -pore" system.…”

Section: Modellingmentioning

confidence: 99%

Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres

Barat

Crane

Ruskin

2008

Journal of Pharmaceutical and Biomedical Analysis

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Summary. Using poly(lactide-co-glycolide) (PLGA) particles for drug encapsulation and delivery has recently gained considerable popularity for a number of reasons. An advantage in one sense, but a drawback of PLGA use in another, is that drug delivery systems made of this material can provide a wide range of dissolution profiles, due to their internal structure and properties related to particles' manufacture. The advantages of enriching particulate drug design experimentation with computer models, are evident with simulations used to predict and optimize design, as well as indicate choice of best manufacturing parameters. In the present work, we seek to understand the phenomena observed for PLGA micro-and nanospheres, through Cellular Automata (CA) agent-based Monte Carlo (MC) models. Systems are studied both over large temporal scales, (capturing slow erosion of PLGA) and for various spatial configurations (capturing initial as well as dynamic morphology). The major strength of this multi-agent approach is to observe dissolution directly, by monitoring the emergent behaviour: the dissolution profile manifested, as a sphere erodes. Different problematic aspects of the modelling process are discussed in details in this paper. The models were tested on experimental data from literature, demonstrating very good performance. Quantitative discussion is provided throughout the text in order to make a demonstration of the use in practice of the proposed model.

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Section: Modellingmentioning

confidence: 99%

Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres

Barat

Crane

Ruskin

2008

Journal of Pharmaceutical and Biomedical Analysis

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show abstract

“…Equally, other experimental studies have reported cases of spheres with initial occlusions much larger than the Stokes-Einstein diameter of the microencapsulated molecule [2,3]. Nevertheless, as long as the proteins undergo very restricted diffusion through pores of i) the same order of magnitude as the proteins themselves or ii) slightly larger, but where other secondary phenomena, not specifically modelled here, form obstacles 4 , it is appropriate to treat diffusion by individual random walks of a given number of agents [14,17]. In such cases, multi-agent systems seem reasonable approximations for a "protein -PLGA -pore" system.…”

Section: Modellingmentioning

confidence: 96%

3D Multi-agent models for protein release from PLGA spherical particles with complex inner morphologies

2008

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In order to better understand and predict the release of proteins from bioerodible micro-or nanospheres, it is important to know the influences of different initial factors on the release mechanisms. Often though it is difficult to assess what exactly is at the origin of a certain dissolution profile. We propose here a new class of fine-grained multi-agent models built to incorporate increasing complexity, permitting the exploration of the role of different parameters, especially that of the internal morphology of the spheres, in the exhibited release profile. This approach, based on Monte-Carlo (MC) and Cellular Automata (CA) techniques, has permitted the testing of various assumptions and hypotheses about several experimental systems of nanospheres encapsulating proteins. Results have confirmed that this modelling approach has increased the resolution over the complexity involved, opening promising perspectives for future developments, especially complementing in vitro experimentation.

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“…The value of "n" depends on the shape of the samples and for thin films, cylinders, cubes and spheres it is 0.5, 0.45, 0.44 and 0.43 for the mechanism of diffusion and 1.0, 0.89, 0.87 and 0.85 for the transport mechanism through the polymer chains [29]. Figure 5 presents the curves showing the release of the calcium ions used as an active ingredient in the range of 0-60 % of the total ions concentration as proposed by Kosmidis et al [29]. The curve was analyzed using the nonlinear regression analysis, and the parameters "k" and "n" from the power law equations were obtained.…”

Section: Digestion Of the Gels In An Artificial Stomachmentioning

confidence: 99%

New controlled release material: aerated egg white gels induced by calcium ions

Tomczyńska‐Mleko

Handa²,

Wesołowska–Trojanowska

et al. 2016

Eur Food Res Technol

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by Fickian diffusion through the swelling matrix and it was faster for the gels with higher concentration of calcium. An increase in calcium concentration caused an increase in surface roughness of the aerated gels. There were linear correlations between the quadratic mean of the surface roughness and "n" coefficient from the Ritger and Peppas equation and between the maximum roughness size and "n". The increased calcium concentration made the gel microstructure more particulate and the surface rougher, which enabled faster proteolysis of the gel in an artificial stomach and faster diffusion of calcium ions.Keywords Aerated · Egg white · Gel · Release · Microstructure · Surface properties · Rheology Abstract The aim of the research was to use low-mineral egg white albumin isolate to obtain aerated calcium ioninduced gels and to investigate their aptitude as matrices for active ingredients release. Aerated gels were prepared by adding calcium ions to pre-heated protein dispersions with simultaneous aeration. 20 mM calcium concentration was an optimal concentration at which the maximum viscosity and hardness of the gels were found. For higher concentrations of calcium ions (25-30 mM), aerated gels were characterized by lower values of the moduli and tangent of the phase angle was larger for aerated gels which indicated more viscous character than that of non-aerated gels. Increased ions concentration causes higher aggregation of protein matrix and less smooth microstructure of the interface between the gel and air. An increase in calcium concentration from 5 to 30 mM caused an increase in an average bubble size. The release of calcium ions from aerated gels was measured in an artificial stomach. It occurred * Stanisław Mleko

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Analysis of Case II drug transport with radial and axial release from cylinders

Cited by 71 publications

References 8 publications

Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres

Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres

3D Multi-agent models for protein release from PLGA spherical particles with complex inner morphologies

New controlled release material: aerated egg white gels induced by calcium ions

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