The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Nobuyuki Amano - One of the best experts on this subject based on the ideXlab platform.
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Utility of Göttingen minipigs for Prediction of Human Pharmacokinetic Profiles After Dermal Drug Application.
Pharmaceutical research, 2017Co-Authors: Syunsuke Yamamoto, Masatoshi Karashima, Noriyasu Sano, Chiharu Fukushi, Kimio Tohyama, Yuta Arai, Hideki Hirabayashi, Nobuyuki AmanoAbstract:Although Gottingen minipigs have been widely used for the evaluation of skin absorption, the correlation of minipig skin Permeability with human skin absorption remains unclear. This study was designed to investigate the prediction of human plasma concentrations after dermal application of drug products using skin Permeability Data obtained from minipigs. First, in vitro skin permeabilities of seven marketed transdermal drug products were evaluated in minipigs, and compared with in vitro human skin Permeability Data. Next, plasma concentration-time profiles in humans after dermal applications were simulated using the in vitro minipig skin Permeability Data. Finally, the in vitro-in vivo correlation of minipig skin Permeability was assessed. The in vitro skin permeabilities in minipigs were correlated strongly with in vitro human skin Permeability Data for the same drug products, indicating the utility of minipig skin as an alternative to human skin for in vitro studies. The steady-state plasma concentration or the maximum concentration of drugs was within 2-fold of the clinical Data. Bioavailability was approximately 3-fold lower than in vitro permeated fraction. Predictions using in vitro skin Permeability Data in Gottingen minipig skin can reproduce the human pharmacokinetic profile, although the prediction of in vivo skin absorption underestimates human absorption.
Monica Riva - One of the best experts on this subject based on the ideXlab platform.
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Interpretation of multi-scale Permeability Data through an information theory perspective
Hydrology and Earth System Sciences, 2020Co-Authors: Aronne Dell'oca, Alberto Guadagnini, Monica RivaAbstract:Abstract. We employ elements of information theory to quantify (i) the information content related to Data collected at given measurement scales within the same porous medium domain and (ii) the relationships among information contents of Datasets associated with differing scales. We focus on gas Permeability Data collected over Berea Sandstone and Topopah Spring Tuff blocks, considering four measurement scales. We quantify the way information is shared across these scales through (i) the Shannon entropy of the Data associated with each support scale, (ii) mutual information shared between Data taken at increasing support scales, and (iii) multivariate mutual information shared within triplets of Datasets, each associated with a given scale. We also assess the level of uniqueness, redundancy and synergy (rendering, i.e., information partitioning) of information content that the Data associated with the intermediate and largest scales provide with respect to the information embedded in the Data collected at the smallest support scale in a triplet. Highlights. Information theory allows characterization of the information content of Permeability Data related to differing measurement scales. An increase in the measurement scale is associated with quantifiable loss of information about Permeability. Redundant, unique and synergetic contributions of information are evaluated for triplets of Permeability Datasets, each taken at a given scale.
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Interpretation of Multi-scale Permeability Data through an Information Theory Perspective
2019Co-Authors: Aronne Dell'oca, Alberto Guadagnini, Monica RivaAbstract:Abstract. We employ elements of Information Theory to quantify (i) the information content related to Data collected at given measurement scales within the same porous medium domain, and (ii) the relationships among Information contents of Datasets associated with differing scales. We focus on gas Permeability Data collected over a Berea Sandstone and a Topopah Spring Tuff blocks, considering four measurement scales. We quantify the way information is shared across these scales through (i) the Shannon entropy of the Data associated with each support scale, (ii) mutual information shared between Data taken at increasing support scales, and (iii) multivariate mutual information shared within triplets of Datasets, each associated with a given scale. We also assess the level of uniqueness, redundancy and synergy (rendering, i.e., the information partitioning) of information content that the Data associated with the intermediate and largest scales provide with respect to the information embedded in the Data collected at the smallest support scale in a triplet.
Gary P. Moss - One of the best experts on this subject based on the ideXlab platform.
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Model fitting for small skin Permeability Data sets: hyperparameter optimisation in Gaussian Process Regression
The Journal of pharmacy and pharmacology, 2018Co-Authors: Parivash Ashrafi, Yi Sun, Neil Davey, Roderick Adams, Simon Wilkinson, Gary P. MossAbstract:The aim of this study was to investigate how to improve predictions from Gaussian Process models by optimising the model hyperparameters. Optimisation methods, including Grid Search, Conjugate Gradient, Random Search, Evolutionary Algorithm and Hyper-prior, were evaluated and applied to previously published Data. Data sets were also altered in a structured manner to reduce their size, which retained the range, or 'chemical space' of the key descriptors to assess the effect of the Data range on model quality. The Hyper-prior Smoothbox kernel results in the best models for the majority of Data sets, and they exhibited significantly better performance than benchmark quantitative structure-Permeability relationship (QSPR) models. When the Data sets were systematically reduced in size, the different optimisation methods generally retained their statistical quality, whereas benchmark QSPR models performed poorly. The design of the Data set, and possibly also the approach to validation of the model, is critical in the development of improved models. The size of the Data set, if carefully controlled, was not generally a significant factor for these models and that models of excellent statistical quality could be produced from substantially smaller Data sets. © 2018 Royal Pharmaceutical Society.
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Quantitative structure-Permeability relationships for percutaneous absorption: re-analysis of steroid Data.
International journal of pharmaceutics, 2002Co-Authors: Gary P. Moss, Mark T D CroninAbstract:Certain molecules, in particular steroids, have been observed to be outliers to quantitative structure-Permeability relationships (QSPRs) for skin Permeability (k(p)). Recently, however, many of the historical skin Permeability Data for these compounds have been found not to be consistent with more modern Data. In this study QSPRs were re-analysed replacing the originally published steroid Permeability Data with those from more recent studies. A highly significant QSPR describing skin Permeability in terms of the octanol-water partition coefficient (logP) and molecular weight (MW) was derived (log k(p)=0.74 logP-0.0091MW-2.39). This model is similar to those published previously. Statistical analysis of the residuals from the QSPR determined that the steroids are no longer outliers to this model. Thus, they may be considered to penetrate the skin by the same means as the majority of exogenous chemicals in this model.
Syunsuke Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Utility of Göttingen minipigs for Prediction of Human Pharmacokinetic Profiles After Dermal Drug Application.
Pharmaceutical research, 2017Co-Authors: Syunsuke Yamamoto, Masatoshi Karashima, Noriyasu Sano, Chiharu Fukushi, Kimio Tohyama, Yuta Arai, Hideki Hirabayashi, Nobuyuki AmanoAbstract:Although Gottingen minipigs have been widely used for the evaluation of skin absorption, the correlation of minipig skin Permeability with human skin absorption remains unclear. This study was designed to investigate the prediction of human plasma concentrations after dermal application of drug products using skin Permeability Data obtained from minipigs. First, in vitro skin permeabilities of seven marketed transdermal drug products were evaluated in minipigs, and compared with in vitro human skin Permeability Data. Next, plasma concentration-time profiles in humans after dermal applications were simulated using the in vitro minipig skin Permeability Data. Finally, the in vitro-in vivo correlation of minipig skin Permeability was assessed. The in vitro skin permeabilities in minipigs were correlated strongly with in vitro human skin Permeability Data for the same drug products, indicating the utility of minipig skin as an alternative to human skin for in vitro studies. The steady-state plasma concentration or the maximum concentration of drugs was within 2-fold of the clinical Data. Bioavailability was approximately 3-fold lower than in vitro permeated fraction. Predictions using in vitro skin Permeability Data in Gottingen minipig skin can reproduce the human pharmacokinetic profile, although the prediction of in vivo skin absorption underestimates human absorption.
Fausto Gallucci - One of the best experts on this subject based on the ideXlab platform.
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New high temperature sealing technique and Permeability Data for hollow fiber BSCF perovskite membranes
Chemical Engineering and Processing - Process Intensification, 2016Co-Authors: L Di Felice, Vesna Middelkoop, V Anzoletti, Frans Snijkers, Van M Martin Sint Annaland, Fausto GallucciAbstract:Abstract Oxygen permeation through BSCF perovskite hollow fiber membranes has been investigated in a laboratory scale reactor in a temperature range of 850–1000 °C at atmospheric pressure. An experimental study was conducted with particular focus on a new sealing technique which was found to provide fully gas-tight conditions with a 100% success rate for the 6 membranes reported in this work (and for 15 membranes in total). An overview of experimental tests on other sealants proposed in the literature is given. A new method for checking the sealing is suggested that allows detecting the possible leakages in all the parts of the membrane module. A loose-end reactor with a shell-and-tube layout is presented which allows accurate measurements of both gas leakages (if any) and product gas composition in a wide range of operating conditions (flow rates on both the permeate and feed side, O 2 feed partial pressure, temperature). Permeation fluxes were studied for BSCF membranes with different thicknesses (0.2 and 0.5 mm) using He as sweep gas. The O 2 flux increased with both increasing the O 2 driving force (i.e., the O 2 partial pressure difference through the dense ceramic layer) and the reactor temperature. Long term tests (600 h) have been carried out proving the high stability of both the membranes used and the newly proposed sealing technique. The presence of both O 2 bulk diffusion and surface exchange resistance is suggested to limit the permeation rate of the ceramic hollow fibers for the range of wall thicknesses investigated. Finally, LSCF capillaries have also been successfully sealed allowing to extend the use of the proposed gas tight sealing system to different compositions of hollow fibers perovskite membranes.