The Experts below are selected from a list of 40014 Experts worldwide ranked by ideXlab platform
Alex Avdeef - One of the best experts on this subject based on the ideXlab platform.
-
skin PAMPA a new method for fast prediction of skin penetration
European Journal of Pharmaceutical Sciences, 2012Co-Authors: Bálint Sinkó, Alex Avdeef, T M Garrigues, Gyorgy T Balogh, Zsombor Kristof Nagy, Oksana Tsinman, Krisztina TakacsnovakAbstract:Abstract The goal of this study was to develop a quick, reliable, and cost-effective permeability model for predicting transdermal penetration of compounds. The Parallel Artificial Membrane Permeability Assay (PAMPA) was chosen for this purpose, as it already has been successfully used for estimating passive gastrointestinal absorption and blood–brain barrier permeability. To match the permeability of the rate-limiting barrier in human skin, synthetic certramides, which are analogs of the ceramides present in the stratum corneum, were selected for the skin–PAMPA model. The final skin–PAMPA membrane lipid mixture (certramide, free fatty acid, and cholesterol) was selected and optimized based on data from three different human skin databases and the final model was found to correlate well to all of the databases. The reproducibility of the skin–PAMPA model was investigated and compared to that of other PAMPA models. The homogeneity of the filter-impregnated lipid mixture membrane was confirmed with Raman microscopy. It was shown that skin–PAMPA is a quick and cost-effective research tool that can serve as a useful model of skin penetration in pharmaceutical and cosmetic research.
-
PAMPA--critical factors for better predictions of absorption.
Journal of pharmaceutical sciences, 2007Co-Authors: Alex Avdeef, Stefanie Bendels, Bernard Faller, Manfred Kansy, Kiyohiko Sugano, Yukinori YamauchiAbstract:PAMPA, log P(OCT), and Caco-2 are useful tools in drug discovery for the prediction of oral absorption, brain penetration and for the development of structure-permeability relationships. Each approach has its advantages and limitations. Selection criteria for methods are based on many different factors: predictability, throughput, cost and personal preferences (people factor). The PAMPA concerns raised by Galinis-Luciani et al. (Galinis-Luciani et al., 2007, J Pharm Sci, this issue) are answered by experienced PAMPA practitioners, inventors and developers from diverse research organizations. Guidelines on how to use PAMPA are discussed. PAMPA and PAMPA-BBB have much better predictivity for oral absorption and brain penetration than log P(OCT) for real-world drug discovery compounds. PAMPA and Caco-2 have similar predictivity for passive oral absorption. However, it is not advisable to use PAMPA to predict absorption involving transporter-mediated processes, such as active uptake or efflux. Measurement of PAMPA is much more rapid and cost effective than Caco-2 and log P(OCT). PAMPA assay conditions are critical in order to generate high quality and relevant data, including permeation time, assay pH, stirring, use of cosolvents and selection of detection techniques. The success of using PAMPA in drug discovery depends on careful data interpretation, use of optimal assay conditions, implementation and integration strategies, and education of users.
-
PAMPA--a drug absorption in vitro model 13. Chemical selectivity due to membrane hydrogen bonding: in combo comparisons of HDM-, DOPC-, and DS-PAMPA models.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2006Co-Authors: Alex Avdeef, Oksana TsinmanAbstract:This study compares the intrinsic permeability coefficients of 40 drug molecules, obtained by three popular variants of the PAMPA assay, based on: (a) n-hexadecane, (b) 2% w/v dioleyoylphosphatidylcholine in n-dodecane, and (c) 20% w/v lecithin in n-dodecane, the HDM-, DOPC-, DS-PAMPA models, respectively. It was shown that PAMPA permeability values consistently rank in magnitude according to: DS>DOPC>HDM, with molecules like metoprolol showing 1000-fold greater permeability in DS than in HDM. Abraham descriptors were used to rationalize these observations. Water-solubilized polar molecules form very strong H-bonds with the solvent. Such molecules need to break these bonds in order to enter the pure alkane phase, which, in turn, offers no compensating H-bond solvation. Thus, more energy appears to be needed for a polar molecule to penetrate a pure alkane barrier, compared to a barrier possessing some H-bond interactions. The 20% phospholipid content of the DS-PAMPA lipid may be thought to ease the permeation process, by offering a compensating source of H-bonding within the membrane phase.
-
The rise of PAMPA.
Expert opinion on drug metabolism & toxicology, 2005Co-Authors: Alex AvdeefAbstract:The parallel artificial membrane permeability assay (PAMPA), as a passive-permeability screen, is a possible low-cost alternative to cellular models for the earliest ADME primary screening of research compounds. Its popularity in the industry has risen rapidly. This review examines state-of-the-art PAMPA methods. The various covered topics include: different lipid formulations, the quantitative relationships between hexadecane, dioyleyoylphosphatidycholine and Double-Sink PAMPA measurements, the use of individual-well stirring, issues of ultraviolet sensitivity, timing strategies, reproducibility of measurements, the correct pH to perform the measurement to avoid aqueous boundary layer problems, the pKa(flux) method for determining intrinsic permeability coefficients and the cosolvent method for very insoluble molecules. Examples of the determination of permeability of very difficult molecules, but molecules that are well absorbed, are given. Carefully gathered evidence in support of the use of the Double-Sink PAMPA model is presented. The review concludes with a binning strategy to predict human intestinal absorption, based on the use of the sum of permeability coefficients, measured at gradient pH 5.0, 6.2 and 7.4. Opinions regarding the future of PAMPA are offered.
-
Advances in screening for membrane permeability: high-resolution PAMPA for medicinal chemists.
Drug discovery today. Technologies, 2004Co-Authors: Manfred Kansy, Alex Avdeef, Holger FischerAbstract:The majority of orally administered drugs are described to be passively transported across the lipophilic cell membranes [Lennernas, H. et al. (1994) Intestinal drug absorption during induced net water absorption in human; a mechanistic study using antipyrine, atenolol and enalaprilat. Br. J. Clin. Pharmacol. 37, 589-596; [1] Artursson, P. Application of physicochemical properties of molecules to predict intestinal permeability. Proceedings of the AAPS Workshop on Permeability Definitions and Regulatory Standards, Arlington, VA, 17-19 August 1998] [2]. Parallel artificial membrane permeability assay (PAMPA), as a passive-permeability screen with focus on the simulation of transcellular processes, is an excellent compliment to cellular models in absorption, distribution, metabolism, excretion (ADME) screening of research compounds. Being fast, versatile, and low-cost, PAMPA is a compelling and biologically relevant model of transport. The problem of low solubility of research compounds has been largely eliminated in the PAMPA method. This review will emphasize how high-resolution PAMPA can help in the design of structural features into molecules to improve their absorption-related properties.:
Breccia, Javier Dario - One of the best experts on this subject based on the ideXlab platform.
-
The flavonoid degrading fungus Acremonium sp. DSM 24697 produces two diglycosidases with different specificities
'Springer Science and Business Media LLC', 2019Co-Authors: Weiz Gisela, Mazzaferro Laura, Neher, Bárbara Daniela, Kotik Michael, Halada Petr, Křen Vladimír, Breccia, Javier DarioAbstract:Diglycosidases hydrolyze the heterosidic linkage of diglycoconjugates, releasing the disaccharide and the aglycone. Usually, these enzymes do not hydrolyze or present only low activities towards monoglycosylated compounds. The flavonoid degrading fungus Acremonium sp. DSM 24697 produced two diglycosidases, which were termed 6-O-α-rhamnosyl-β-glucosidase I and II (αRβG I and II) because of their function of releasing the disaccharide rutinose (6-O-α-L-rhamnosyl-β-D-glucose) from the diglycoconjugates hesperidin or rutin. In this work, the genome of Acremonium sp. DSM 24697 was sequenced and assembled with a size of ~ 27 Mb. The genes encoding αRβG I and II were expressed in Pichia pastoris KM71 and the protein products were purified with apparent molecular masses of 42 and 82 kDa, respectively. A phylogenetic analysis showed that αRβG I grouped in glycoside hydrolase family 5, subfamily 23 (GH5), together with other fungal diglycosidases whose substrate specificities had been reported to be different from αRβG I. On the other hand, αRβG II grouped in glycoside hydrolase family 3 (GH3) and thus is the first GH3 member that hydrolyzes the heterosidic linkage of rutinosylated compounds. The substrate scopes of the enzymes were different: αRβG I showed exclusive specificity toward 7-O-β-rutinosyl flavonoids, whereas αRβG II hydrolyzed both 7-O-β-rutinosyl- and 3-O-β-rutinosyl- flavonoids. None of the enzymes displayed activity toward 7-O-β-neohesperidosyl- flavonoids. The recombinant enzymes also exhibited transglycosylation activities, transferring rutinose from hesperidin or rutin onto various alcoholic acceptors. The different substrate scopes of αRβG I and II may be part of an optimized strategy of the original microorganism to utilize different carbon sources.Fil: Weiz, Gisela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; Argentina. Universidad Nacional de La PAMPA; ArgentinaFil: Mazzaferro, Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; Argentina. Universidad Nacional de La PAMPA; ArgentinaFil: Kotik, Michael. Biology Centre of the Academy of Sciences of the Czech Republic; República ChecaFil: Neher, Bárbara Daniela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; Argentina. Universidad Nacional de La PAMPA; ArgentinaFil: Halada, Petr. Biology Centre of the Academy of Sciences of the Czech Republic; República ChecaFil: Křen, Vladimír. Biology Centre of the Academy of Sciences of the Czech Republic; República ChecaFil: Breccia, Javier Dario. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; Argentina. Universidad Nacional de La PAMPA; Argentin
-
The flavonoid degrading fungus Acremonium sp. DSM 24697 produces two diglycosidases with different specificities
'Springer Science and Business Media LLC', 2019Co-Authors: Weiz Gisela, Mazzaferro Laura, Neher, Bárbara Daniela, Kotik Michael, Halada Petr, Kren Vladimír, Breccia, Javier DarioAbstract:Diglycosidases hydrolyze the heterosidic linkage of diglycoconjugates, releasing the disaccharide and the aglycone. Usually, these enzymes do not hydrolyze or present only low activities towards monoglycosylated compounds. The flavonoid degrading fungus Acremonium sp. DSM 24697 produced two diglycosidases, which were termed 6-O-α-rhamnosyl-β-glucosidase I and II (αRβG I and II) because of their function of releasing the disaccharide rutinose (6-O-α-L-rhamnosyl-β-D-glucose) from the diglycoconjugates hesperidin or rutin. In this work, the genome of Acremonium sp. DSM 24697 was sequenced and assembled with a size of ~ 27 Mb. The genes encoding αRβG I and II were expressed in Pichia pastoris KM71 and the protein products were purified with apparent molecular masses of 42 and 82 kDa, respectively. A phylogenetic analysis showed that αRβG I grouped in glycoside hydrolase family 5, subfamily 23 (GH5), together with other fungal diglycosidases whose substrate specificities had been reported to be different from αRβG I. On the other hand, αRβG II grouped in glycoside hydrolase family 3 (GH3) and thus is the first GH3 member that hydrolyzes the heterosidic linkage of rutinosylated compounds. The substrate scopes of the enzymes were different: αRβG I showed exclusive specificity toward 7-O-β-rutinosyl flavonoids, whereas αRβG II hydrolyzed both 7-O-β-rutinosyl- and 3-O-β-rutinosyl- flavonoids. None of the enzymes displayed activity toward 7-O-βneohesperidosyl- flavonoids. The recombinant enzymes also exhibited transglycosylation activities, transferring rutinose from hesperidin or rutin onto various alcoholic acceptors. The different substrate scopes of αRβG I and II may be part of an optimized strategy of the original microorganism to utilize different carbon sources.Fil: Weiz, Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Mazzaferro, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Kotik, Michael. Czech Academy Of Sciences.; República ChecaFil: Neher, Bárbara Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Halada, Petr. Czech Academy Of Sciences.; República ChecaFil: Kren, Vladimir. Czech Academy Of Sciences.; República ChecaFil: Breccia, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; Argentin
-
Enzyme-mediated transglycosylation of rutinose (6-O-α-L-rhamnosyl-D-glucose) to phenolic compounds by a diglycosidase from Acremonium sp. DSM 24697
'Wiley', 2019Co-Authors: Mazzaferro Laura, Weiz Gisela, Kotik Michael, Braun, Lucas Ezequiel, Pelantová Helena, Kren Vladimír, Breccia, Javier DarioAbstract:The structure of the carbohydrate moiety of a natural phenolic glycoside can have a significant effect on the molecular interactions and physicochemical and pharmacokinetic properties of the entire compound, which may include anti-inflammatory and anticancer activities. The enzyme 6-O-α-rhamnosyl-β-glucosidase (EC 3.2.1.168) has the capacity to transfer the rutinosyl moiety (6-O-α-L-rhamnopyranosylβ-D-glucopyranose) from 7-O-rutinosylated flavonoids to hydroxylated organic compounds. This transglycosylation reaction was optimized using hydroquinone (HQ) and hesperidin as rutinose acceptor and donor, respectively. Since HQ undergoes oxidation in a neutral to alkaline aqueous environment, the transglycosylation process was carried out at pH values 6.0. The structure of 4-hydroxyphenyl-β-rutinoside was confirmed by NMR, that is, a single glycosylated product with a free hydroxyl group was formed. The highest yield of 4-hydroxyphenyl-β-rutinoside (38%, regarding hesperidin) was achieved in a 2-h process at pH 5.0 and 30 ◦C, with 36 mM OH-acceptor and 5% (v/v) cosolvent. Under the same conditions, the enzyme synthesized glycoconjugates of various phenolic compounds (phloroglucinol, resorcinol, pyrogallol, catechol), with yields between 12% and 28% and an apparent direct linear relationship between the yield and the pKa value of the aglycon. This work is a contribution to the development of convenient and sustainable processes for the glycosylation of small phenolic compounds.Fil: Mazzaferro, Laura. Universidad Nacional de La PAMPA; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; ArgentinaFil: Weiz, Gisela. Universidad Nacional de La PAMPA; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; ArgentinaFil: Braun, Lucas Ezequiel. Universidad Nacional de La PAMPA; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; ArgentinaFil: Kotik, Michael. Czech Academy of Sciences. Institute of Organic Chemistry and Biochemistry; República ChecaFil: Pelantová, Helena. Czech Academy of Sciences. Institute of Organic Chemistry and Biochemistry; República ChecaFil: Kren, Vladimír. Czech Academy of Sciences. Institute of Organic Chemistry and Biochemistry; República ChecaFil: Breccia, Javier Dario. Universidad Nacional de La PAMPA; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas | Universidad Nacional de la PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de la PAMPA. Grupo Vinculado Fundacion Centro de Salud E Investigaciones Medicas.; Argentin
-
Screening and quantification of the enzymatic deglycosylation of the plant flavonoid rutin by UV-visible spectrometry
Elsevier, 2017Co-Authors: Weiz Gisela, Breccia, Javier Dario, Mazzaferro LauraAbstract:Rutin is a plant flavonoid constituted by the flavonol quercetin 3-O-linked to the disaccharide rutinose (quercetin 3-O-(6-O-α-L-rhamnopyranosyl-β-D-glucopyranoside)). The enzymatic deglycosylation of rutin is usually assessed by means of the standard method for flavonoid quantification (high performance liquid chromatography, HPLC). In this work, we have developed a spectrophotometric method for the quantification of the released quercetin. After the enzymatic reaction, quercetin is extracted with ethyl acetate, and subsequently oxidized under basic conditions. The absorbance of quercetin autooxidation products at 320 nm was correlated with the quercetin concentration by linear regression (molar extinction coefficient 26.5 (± 0.3) × 103 M-1 cm-1). The convenience of this method relies on the enzymatic activity quantification using the natural substrate by UV-visible spectrometry. Moreover, the simplicity and speed of analysis allows its application for the assay of a large number of samples.Fil: Weiz, Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Breccia, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Mazzaferro, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; Argentin
-
Bacteria as source of diglycosidase activity: actinoplanes missouriensis produces 6-O-α-l-rhamnosyl-β-d-glucosidase active on flavonoids
Springer Heidelberg, 2015Co-Authors: Neher, Bárbara Daniela, Mazzaferro Laura, Breccia, Javier Dario, Kotik Michael, Oyhenart Jorge, Halada Petr, Křen VladimírAbstract:Bacteria represent an underexplored source of diglycosidases. Twenty-five bacterial strains from the genera Actinoplanes, Bacillus, Corynebacterium, Microbacterium, and Streptomyces were selected for their ability to grow in diglycosylated flavonoids-based media. The strains Actinoplanes missouriensis and Actinoplanes liguriae exhibited hesperidin deglycosylation activity (6-O-α-L-rhamnosyl-β-D-glucosidase activity, EC 3.2.1.168), which was 3 to 4 orders of magnitude higher than the corresponding monoglycosidase activities. The diglycosidase production was confirmed in A. missouriensis by zymographic assays and NMR analysis of the released disaccharide, rutinose. The gene encoding the 6-O-α-L-rhamnosyl-β-D-glucosidase was identified in the genome sequence of A. missouriensis 431T (GenBank accession number BAL86042.1) and functionally expressed in Escherichia coli. The recombinant protein hydrolyzed hesperidin and hesperidin methylchalcone, but not rutin, which indicates its specificity for 7-O-rutinosylated flavonoids. The protein was classified into the glycoside hydrolase family 55 (GH55) in contrast to the known eukaryotic diglycosidases, which belong to GH1 and GH5. These findings demonstrate that organisms other than plants and filamentous fungi can contribute to an expansion of the diglycosidase toolbox.Fil: Neher, Bárbara Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Mazzaferro, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Kotik, Michael. Academy of Sciences of the Czech Republic. Institute of Microbiology; República ChecaFil: Oyhenart, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Halada, Petr. Academy of Sciences of the Czech Republic. Institute of Microbiology; República ChecaFil: Breccia, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA. Universidad Nacional de La PAMPA. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La PAMPA; ArgentinaFil: Křen, Vladimír. Academy of Sciences of the Czech Republic. Institute of Microbiology; República Checa; República Chec
Yoshinori Aso - One of the best experts on this subject based on the ideXlab platform.
-
Biopharmaceutics Classification by High Throughput Solubility Assay and PAMPA
Drug development and industrial pharmacy, 2004Co-Authors: Kouki Obata, Kiyohiko Sugano, Minoru Machida, Yoshinori AsoAbstract:The purpose of the present study was to examine the relevancy of the high throughput solubility assay and permeability assay to the biopharmaceutics classification system (BCS). Solubility and permeability were measured by high throughput solubility assay (HTSA) and parallel artificial membrane permeation assay (PAMPA), respectively. High throughput solubility assay was performed using simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid without bile acid (SIF, pH 6.8). We categorize 18 drugs based on the BCS using HTSA and PAMPA. Fourteen out of 18 drugs were correctly classified (78% success rate). The result of the present study showed that HTSA could predict BCS class with a high success rate, and PAMPA could also be useful to predict the permeation of drugs.
James E. Polli - One of the best experts on this subject based on the ideXlab platform.
-
Comparison of drug permeabilities and BCS classification: three lipid-component PAMPA system method versus Caco-2 monolayers.
The AAPS journal, 2010Co-Authors: Zeynep S. Teksin, Paul R. Seo, James E. PolliAbstract:A three lipid-component parallel artificial membrane permeability assay (PAMPA) system was previously devised and evaluated (1). Denoted A-PAMPA for anionic-PAMPA, A-PAMPA was designed to mimic the lipid composition of the enterocyte's plasma membrane and included 1,2-dioleoyl-sn-glycero-3-[phospho-l-serine] (PS18:1) as an anionic lipid component. A-PAMPA also consists of 1,2-dioleoyl-sn-glycero-3-phosphocholine (PC18:1) and cholesterol. Metoprolol flux across A-PAMPA was measured, as well as across three other PAMPA systems (1). Results indicated that metoprolol transport across A-PAMPA was dominated by an ion-pair-mediated mechanism (i.e., metoprolol-PS18:1 complex). The objective in the present study was to compare the performance of this three lipid-component PAMPA system to Caco-2 monolayers, in terms of screening for drug permeability values. Several development laboratories employ PAMPA membranes in candidate selection, in part because of other experimental approaches, such as Caco-2 and MDCK monolayers, are more labor-intensive and expensive (2–8). However, A-PAMPA has not been previously evaluated to identify drugs that are likely to exhibit high permeability in Caco-2 BCS testing.
-
Ion pair-mediated transport of metoprolol across a three lipid-component PAMPA system.
Journal of controlled release : official journal of the Controlled Release Society, 2006Co-Authors: Zeynep S. Teksin, Kelli Hom, Anand Balakrishnan, James E. PolliAbstract:Parallel Artificial Membrane Permeability Assay (PAMPA) is a method to screen drug candidates for membrane permeability. The objective was to characterize the transport of a model weak base, metoprolol, across a three lipid-component PAMPA system (denoted A-PAMPA, for anionic-PAMPA) and challenge ion pairing as a mechanism for metoprolol transport. A-PAMPA was designed to mimic the lipid composition of the enterocyte's plasma membrane and included 1,2-dioleoyl-sn-glycero-3-[phospho-l-serine] (PS18:1) as an anionic lipid-component. Metoprolol flux was measured across A-PAMPA, as well as across three other PAMPA systems. Permeability studies were conducted under various conditions, with varying pH, ionic strength, and presence/absence of competing cations. Permeabilities of mannitol and benzoic acid, as model neutral and anionic solutes, were also measured. PAMPA membrane fluidity was inferred from anisotropy measurements in liposomes. Ion pairing between metoprolol and PS18:1 was assessed via NMR. Metoprolol transport across A-PAMPA was dominated by an ion pair-mediated mechanism (i.e. metoprolol-PS18:1 complex), rather than a membrane fluidity-mediated mechanism. Compared to other PAMPA systems, metoprolol permeability across A-PAMPA and PS18:1 was high. Permeability and anisotropy values suggested PS18:1 selectively facilitated metoprolol transport, while neutral lipid did not. Additional studies supporting ion pairing of metoprolol across A-PAMPA showed that a) metoprolol transport was self-inhibited across A-PAMPA but not across neutral lipid PAMPA; b) competing cations reduced metoprolol permeability across A-PAMPA but not across neutral lipid PAMPA; and c) NMR spectrum of a mixture of metoprolol and PS18:1 showed a broadening of some metoprolol peaks, presumably due to metoprolol interaction with anionic lipid. Metoprolol transport across a three lipid-component PAMPA system that contained anionic lipid was facilitated by apparent ion pairing.
-
Lipid composition effect on permeability across PAMPA.
European Journal of Pharmaceutical Sciences, 2006Co-Authors: Paul R. Seo, Zeynep S. Teksin, Joseph P. Y. Kao, James E. PolliAbstract:Abstract The parallel artificial membrane permeability assay (PAMPA) system has promise to rapidly screen drug candidate passive permeability, but has been poorly described in terms of its lipid membrane structure and function. The objective was to investigate the role of PAMPA lipid composition on the permeability of five model compounds. PAMPA was used and employed individual phospholipids that varied in phosphate head group and acyl chain unsaturation. Transport of benzoic acid, taurocholic acid, metoprolol, sucrose, and mannitol was measured. Membrane fluidity was assessed by 1,3-diphenylhexatriene fluorescence anisotropy. Results indicate that compound permeability across PAMPA differed in their sensitivity to membrane lipid composition, where compounds with appreciable permeability (i.e. at least 0.2 × 10−6 cm/s) were possibly sensitive to membrane fluidity and apparent ion pair effects. Benzoic acid permeability ranged 51-fold across membrane types, suggesting acyl chain effect on membrane fluidity. Mannitol, sucrose, and taurocholic acid permeabilities were low and independent of lipid composition. Metoprolol permeability ranged 17-fold and exhibited a markedly high permeability across 1,2-dioleoyl-sn-glycero-3-[phospho- l -serine] due to apparent ion pair-facilitated transport. Compound permeability was lowest across the phosphatidylcholines, which is consistent with phosphatidylcholine exhibiting relatively high membrane rigidity. In contrast to results from phosphatidylethanolamines and phosphatidylserines, acyl chain unsaturation had no effect on permeability across phosphatidylcholines. In conclusion, while much remains unknown about PAMPA structure and subsequent PAMPA permeability, results here from five solutes suggest that, for solutes with appreciable permeability, lipid composition modulated drug permeability through possible membrane fluidity and apparent ion pair influences.
Bálint Sinkó - One of the best experts on this subject based on the ideXlab platform.
-
Related Topic: Use of PAMPA and Artificial Membranes
Skin Permeation and Disposition of Therapeutic and Cosmeceutical Compounds, 2017Co-Authors: Bálint Sinkó, Krisztina Takács-novákAbstract:The following paragraphs describe the options of applying artificial membranes for the prediction of transdermal penetration, focusing mostly on the PAMPA method. A model membrane of PAMPA mimicking skin penetration was first described in 2006, but the need for a more bio-mimetic system has arisen with new industrial tendencies, and a more bio-relevant system was published in 2012. Since its first publication, Skin PAMPA has already been applied by several universities and industrial groups successfully and the first articles, podium, and poster presentations have appeared. Application of the Skin PAMPA model has been extended and examples for testing of semi-solid formulations and transdermal patches are available, besides the standard solution applications.
-
a comparative study of the in vitro permeation of ibuprofen in mammalian skin the PAMPA model and silicone membrane
International Journal of Pharmaceutics, 2016Co-Authors: Lin Luo, Bálint Sinkó, Avnish Patel, M Bell, J I D Wibawa, Jonathan Hadgraft, Majella E LaneAbstract:Human skin remains the membrane of choice when conducting in vitro studies to determine dermal penetration of active pharmaceutical ingredients or xenobiotics. However there are ethical and safety issues associated with obtaining human tissue. For these reasons synthetic membranes, cell culture models or in silico predictive algorithms have been researched intensively as alternative approaches to predict dermal exposure in man. Porcine skin has also been recommended as an acceptable surrogate for topical or transdermal delivery research. Here we examine the in vitro permeation of a model active, ibuprofen, using human or porcine skin, as well as the Parallel Artificial Membrane Permeation Assay (PAMPA) model and silicone membrane. Finite dose studies were conducted in all models using commercial ibuprofen formulations and simple volatile ibuprofen solutions. The dose applied in the PAMPA model was also varied in order to determine the amount of applied formulation which best simulates typical amounts of topical products applied by patients or consumers. Permeation studies were conducted up to 6h for PAMPA and silicone and up to 48h for human and porcine skin. Cumulative amounts permeated at 6h were comparable for PAMPA and silicone, ranging from 91 to 136μg/cm(2) across the range of formulations studied. At 48h, maximum ibuprofen permeation in human skin ranged from 11 to 38μg/cm(2) and corresponding values in porcine skin were 59-81μg/cm(2). A dose of 1μL was confirmed as appropriate for finite dose studies in the PAMPA model. The formulation which delivered the greatest amount of ibuprofen in human skin was also significantly more efficient than other formulations when evaluated in the PAMPA model. The PAMPA model also discriminated between different formulation types (i.e. gel versus solution) compared with other models. Overall, the results confirm the more permeable nature of the PAMPA, silicone membrane and porcine tissue models to ibuprofen compared with human skin. Further finite dose studies to elucidate the effects of individual excipients on the barrier properties of the PAMPA model are needed to expand the applications of this model. The range of actives that are suitable for study using the model also needs to be delineated.
-
PAMPA study of the temperature effect on permeability
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2013Co-Authors: Gábor Vizserálek, Krisztina Takács-novák, Tamás Balogh, Bálint SinkóAbstract:Abstract The purpose of this work was to investigate the temperature dependence of permeability measured by PAMPA method. The effective permeability (log Pe) of seven drugs representing diverse structures and different acid–base properties was determined on three membrane models (GIT, BBB, Skin). The incubation temperature was varied in the range of 15–55 °C with ten degree steps. The intrinsic permeability (log P0) of the compounds is in linear relation with temperature (T). The slope of the log P0 = aT + b regression equation is a good measure of the temperature effect on permeability. Results show intensive and significant temperature dependence of permeability influenced by the properties of the compounds and also by the selected PAMPA model. The Skin PAMPA™ proved to be the most sensitive on temperature alteration, though GIT and BBB PAMPA results were also affected. The compound with acid function showed the lowest temperature dependence, while the permeability of bases increased considerably in response to the increasing temperature. The importance of human-relevant incubation conditions at in vitro assays is concluded for the better in vivo prediction.
-
skin PAMPA a new method for fast prediction of skin penetration
European Journal of Pharmaceutical Sciences, 2012Co-Authors: Bálint Sinkó, Alex Avdeef, T M Garrigues, Gyorgy T Balogh, Zsombor Kristof Nagy, Oksana Tsinman, Krisztina TakacsnovakAbstract:Abstract The goal of this study was to develop a quick, reliable, and cost-effective permeability model for predicting transdermal penetration of compounds. The Parallel Artificial Membrane Permeability Assay (PAMPA) was chosen for this purpose, as it already has been successfully used for estimating passive gastrointestinal absorption and blood–brain barrier permeability. To match the permeability of the rate-limiting barrier in human skin, synthetic certramides, which are analogs of the ceramides present in the stratum corneum, were selected for the skin–PAMPA model. The final skin–PAMPA membrane lipid mixture (certramide, free fatty acid, and cholesterol) was selected and optimized based on data from three different human skin databases and the final model was found to correlate well to all of the databases. The reproducibility of the skin–PAMPA model was investigated and compared to that of other PAMPA models. The homogeneity of the filter-impregnated lipid mixture membrane was confirmed with Raman microscopy. It was shown that skin–PAMPA is a quick and cost-effective research tool that can serve as a useful model of skin penetration in pharmaceutical and cosmetic research.
