Permeability prediction

Van de Waterbeemd, H. Intestinal permeability prediction from theory. In Oral Drug Absorption, Dressman, J. B., Lennemas, H. (eds.), Dekker, New York, 2000, pp. 31-49. 

Van de Waterbeemd, H., Intestinal permeability prediction from theory, in Oral Drug Absorption. Dressman,... 

The VolSurf method was used to produce molecular descriptors, and PLS discriminant analysis (DA) was applied. The statistical model showed two significant latent variables after cross-validation. The 2D PLS score model offers a discrimination between the permeable and less permeable compounds. When the spectrum color is active (Fig. 17.2), red points refer to high permeability, whereas blue points indicate low permeability. There is a region in the central part of the plot with both red and blue compounds. In this region, and in between the two continuous lines, the permeability prediction is less reliable. The permeability model... 

Tab. 17.1. Smiles codes and names of the test set compounds used in Caco-2 external permeability prediction...

Barrier polymers, 3 375-405 applications, 3 405 barrier structures, 3 394-399 carbon dioxide transport, 3 403 flavor and aroma transport, 3 403-405 health and safety factors, 3 405 immiscible blends, 3 396-398 large molecule permeation, 3 388-390 layered structures, 3 394-396 miscible blends, 3 398-399 oxygen transport, 3 402 permanent gas permeation, 3 380-383 permeability prediction, 3 399-401 permeation process, 3 376-380 physical factors affecting permeability, 3 390-393... 

As permeability predictions are required for defining the BCS classification of a drug, it is important to ensure that the conditions chosen should be carefully... 

In Silico Modeling for Blood-Brain Barrier Permeability Predictions... 

Keywords Blood-brain permeability prediction Artificial neural network QSAR... 

Various models for BBB permeability prediction are summarized in terms of their data sets, methods employed, statistical parameters and descriptors, important outcomes in Tables 22.1 and 22.2, respectively. 

Decrease of separation and increase of solute permeability predicted by the oxidation or hydrolysis rate data are shown in Figure Ig. If we increase the concentration of NaOCl from 2 mg/1 to U mg/l, decrease of separation is accelerated because the deterioration rate is proportional to the square of the concentration of the solute. The dotted line shows the tendency of solute decline of the first stage membranes of Toray s spiral wound module which was tested at the Chigasaki Laboratory of Water Reuse Promotion Center over 9 OOOhours( )... 

John Wiley Sons, Inc. (B) Permeability predicted from assumption that 0 is constant. From Paul Koros (1976) Courtesy of John Wiley Sons, Inc. (C) Permeability plotted in accordance with the partial immobilisation model with D constant. From Koros et al. (1976) Courtesy of John Wiley Sons, Inc. 

Caco-2 permeability prediction, based on an experimental model (Caco-2 cells monolayer) that evaluates the intestinal absorption of drugs [30], is derived from known literature datasets - see [31] for a review. This model was confirmed with GPSVS. 

This paper reports an investigation of the effects of porous solid structures on their electrical behaviour at different frequencies (from 100 Hz to 100 kHz). For that, we study different parameters such as formation resistivity factor, cementation factor, chargeability, resistivity index and saturation exponent. Different porous solid structures are quantified from the petrographic image analysis and Hg-injection technique. Then, by using different models we obtain the permeability prediction from the electrical behaviour and structure parameters. 

Fig. 5 Chargeability factor A/can be predicted by a Fig. 6 Permeability prediction from electrical multi-linear model composed by different behaviour and structures parameters of porous parameters formation factor F, water porosity O, solids, k Katz and Thompson model Hg-specific surface Asp and water permeability k for kjsc Johnson, Schwartz and co-workers different textures. model.

Experimental data from the literature [15] concerning freon 113 permeability on a vycor glass membrane were simulated by the 3D network model. An average effective length of each pore was selected in a way that the (non-condensing) helium permeability predicted by the network matches the experimental values, and at the same time gives a porosity and surface area close to the experimental ones. Subsequently, the pore size distribution obtained from porosimetry and the effective pore length were used for the simulation of the condensable vapor permeability. 

The cross-sectional area, AD, of a compound oriented in an amphiphilic gradient such as the air-water or lipid-water interface has been shown to be even more reliable for permeability predictions than the molecular weight [52]. For BBB permeation, the limiting cross-sectional area, AD, was determined as AD 73 A2, and the limiting ionization constants, p Cas, for bases and acids were determined as 9 and 4, respectively [52]. For intestinal barrier permeation, the limiting cross-sectional area was assessed as A D 100 A2, and the limiting ionization constants (pICas) for bases as 9 and for acids as 2 [53]. In this approach, the role of P-gp is again implicit [49]. 

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