The Experts below are selected from a list of 24936 Experts worldwide ranked by ideXlab platform
Dara Fitzpatrick - One of the best experts on this subject based on the ideXlab platform.
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tracking yeast metabolism and the crabtree effect in real time via co2 production using broadband Acoustic Resonance dissolution spectroscopy bards
Journal of Biotechnology, 2020Co-Authors: Rizwan M Ahmed, Jacob Kruse, Sean Mcsweeney, Nicholas Doyle, Cathal Connolly, John P Morrissey, Michael B Prentice, Dara FitzpatrickAbstract:Abstract In this study, a new approach to measure metabolic activity of yeast via the Crabtree effect is described. BARDS is an analytical technique developed to aid powder and tablet characterisation by monitoring changes in the compressibility of a solvent during solute dissolution. It is a rapid and simple method which utilises a magnetic stir bar to mix added solute and induce the Acoustic Resonance of a vessel containing a fixed volume of solvent. In this study it is shown that initiation of fermentation in a yeast suspension, in aqueous buffer, is accompanied by reproducible changes in the frequency of induced Acoustic Resonance. These changes signify increased compressibility of the suspension due to CO2 release by the yeast. A simple standardised BARDS protocol reveals yeast carbon source preferences and can generate quantitative kinetic data on carbon source metabolism which are characteristic of each yeast strain. The Crawford-Woods equation can be used to quantify total gaseous CO2 produced by a given number of viable yeast when supplied with a fixed amount of carbon source. This allows for a value to be calculated for the amount of gaseous CO2 produced by each yeast cell. The approach has the potential to transform the way in which yeast metabolism is tracked and potentially provide an orthogonal or surrogate method to determining viability, vitality and attenuation measurements in the future.
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broadband Acoustic Resonance dissolution spectroscopy bards a rapid test for enteric coating thickness and integrity of controlled release pellet formulations
International Journal of Pharmaceutics, 2018Co-Authors: Anas Alfarsi, Amy Dillon, Jacob Kruse, Ken J Devine, Patricia Sherry, Stephan Henken, Brendan T Griffin, Sean Mcsweeney, Stephen Fitzpatrick, Dara FitzpatrickAbstract:Abstract There are no rapid dissolution based tests for determining coating thickness, integrity and drug concentration in controlled release pellets either during production or post-production. The manufacture of pellets requires several coating steps depending on the formulation. The sub-coating and enteric coating steps typically take up to six hours each followed by additional drying steps. Post production regulatory dissolution testing also takes up to six hours to determine if the batch can be released for commercial sale. The thickness of the enteric coating is a key factor that determines the release rate of the drug in the gastro-intestinal tract. Also, the amount of drug per unit mass decreases with increasing thickness of the enteric coating. In this study, the coating process is tracked from start to finish on an hourly basis by taking samples of pellets during production and testing those using BARDS (Broadband Acoustic Resonance Dissolution Spectroscopy). BARDS offers a rapid approach to characterising enteric coatings with measurements based on reproducible changes in the compressibility of a solvent due to the evolution of air during dissolution. This is monitored Acoustically via associated changes in the frequency of induced Acoustic Resonances. A steady state Acoustic lag time is associated with the disintegration of the enteric coatings in basic solution. This lag time is pH dependent and is indicative of the rate at which the coating layer dissolves. BARDS represents a possible future surrogate test for conventional USP dissolution testing as its data correlates directly with the thickness of the enteric coating, its integrity and also with the drug loading as validated by HPLC.
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Tracking Cocrystallization of Active Pharmaceutical Ingredients with Benzoic Acid Coformer Using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS)
2018Co-Authors: Christopher Kent, Anas Alfarsi, U. Rao B. Khandavilli, Melissa Hanna-brown, Seán Mcsweeney, Jacob Krüse, Simon Lawrence, Dara FitzpatrickAbstract:This study investigates the use of Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) as a detection method for the formation of cocrystals. BARDS is a novel approach that uses reproducible changes in the compressibility of a solvent as a sample dissolves to characterize and differentiate between materials and in this case cocrystallization. Two cocrystal systems with a 1:1 stoichiometry were examined, which used benzoic acid as a coformer with isonicotinamide and with theophylline. Cocrystals were prepared using dry and wet milling for periods from 1 to 40 min, and samples were analyzed using infrared spectroscopy, powder X-ray diffraction, and BARDS. Comparison of the BARDS data with the IR and PXRD data cross-validated the BARDS results. This study shows that BARDS can be used to rapidly assess the formation of these cocrystals at-line when milling or as a relatively low cost tool in preformulation product development. The data can also be used to gauge the unique entrained gas and gas volume generation of the cocrystal samples during dissolution and their dissolution kinetics
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new insights into the mechanism of rehydration of milk protein concentrate powders determined by broadband Acoustic Resonance dissolution spectroscopy bards
Food Hydrocolloids, 2016Co-Authors: Bastiaan Vos, Jacob Kruse, Dara Fitzpatrick, Sean Mcsweeney, Shane V Crowley, Jonathan J Osullivan, Rachel Evanshurson, Rizwan M Ahmed, James A OmahonyAbstract:Abstract This study investigated the transfer of water into milk protein concentrate (MPC) powder particles using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) as a detection method for the first time. BARDS analysis is based on an Acoustic phenomenon which occurs during powder rehydration. Release of air from the powder into the solvent during rehydration leads to outgassing in the solvent, which results in changes in solvent compressibility that are monitored through accompanying changes in induced Resonance frequencies in the dissolution vessel. BARDS confirmed that water transfer into MPC particles became increasingly inhibited as protein content of the powder increased. The reproducibility of the data indicates that air release from internal vacuoles within powder particles in high-protein MPCs is a highly ordered process, occurring over a protracted time scale. Kinetic modelling of gas volume data from BARDS confirmed that the release of occluded air caused the changes in solvent compressibility during rehydration. The physicochemical properties of solubilised protein had a slight inhibitory effect on escape of bubbles from the solvent, but the primary factor limiting gas release from high-protein MPCs was water transfer into powder particles and the concomitant release of occluded air into the solvent. In agreement with many previous studies, cryo-SEM analysis showed that particles in high-protein MPCs were slow to disperse; the current study, in addition, highlights inhibited water transfer into particles as another factor which may contribute to their poor rehydration properties. A potential link between inhibited water transfer and poor dispersibility is proposed.
R Do N Prado - One of the best experts on this subject based on the ideXlab platform.
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integrated zeta flyback electronic ballast to supply high intensity discharge lamps
IEEE Transactions on Industrial Electronics, 2007Co-Authors: Tiago Bandeira Marchesan, J.m. Alonso, M A Dallacosta, R Do N PradoAbstract:This paper proposes a metal halide lamp electronic ballast based on the integration of zeta and flyback converters, which are used to achieve power factor correction and lamp current stabilization, respectively. The proposed integrated converter allows to reduce the number of ballast components without increasing the current stress in the shared switch. Thus, the lamp is supplied with a low-frequency square waveform that avoids the Acoustic Resonance phenomenon. The proposed topology has been implemented and validated by experimental results.
Jacob Kruse - One of the best experts on this subject based on the ideXlab platform.
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tracking yeast metabolism and the crabtree effect in real time via co2 production using broadband Acoustic Resonance dissolution spectroscopy bards
Journal of Biotechnology, 2020Co-Authors: Rizwan M Ahmed, Jacob Kruse, Sean Mcsweeney, Nicholas Doyle, Cathal Connolly, John P Morrissey, Michael B Prentice, Dara FitzpatrickAbstract:Abstract In this study, a new approach to measure metabolic activity of yeast via the Crabtree effect is described. BARDS is an analytical technique developed to aid powder and tablet characterisation by monitoring changes in the compressibility of a solvent during solute dissolution. It is a rapid and simple method which utilises a magnetic stir bar to mix added solute and induce the Acoustic Resonance of a vessel containing a fixed volume of solvent. In this study it is shown that initiation of fermentation in a yeast suspension, in aqueous buffer, is accompanied by reproducible changes in the frequency of induced Acoustic Resonance. These changes signify increased compressibility of the suspension due to CO2 release by the yeast. A simple standardised BARDS protocol reveals yeast carbon source preferences and can generate quantitative kinetic data on carbon source metabolism which are characteristic of each yeast strain. The Crawford-Woods equation can be used to quantify total gaseous CO2 produced by a given number of viable yeast when supplied with a fixed amount of carbon source. This allows for a value to be calculated for the amount of gaseous CO2 produced by each yeast cell. The approach has the potential to transform the way in which yeast metabolism is tracked and potentially provide an orthogonal or surrogate method to determining viability, vitality and attenuation measurements in the future.
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broadband Acoustic Resonance dissolution spectroscopy bards a rapid test for enteric coating thickness and integrity of controlled release pellet formulations
International Journal of Pharmaceutics, 2018Co-Authors: Anas Alfarsi, Amy Dillon, Jacob Kruse, Ken J Devine, Patricia Sherry, Stephan Henken, Brendan T Griffin, Sean Mcsweeney, Stephen Fitzpatrick, Dara FitzpatrickAbstract:Abstract There are no rapid dissolution based tests for determining coating thickness, integrity and drug concentration in controlled release pellets either during production or post-production. The manufacture of pellets requires several coating steps depending on the formulation. The sub-coating and enteric coating steps typically take up to six hours each followed by additional drying steps. Post production regulatory dissolution testing also takes up to six hours to determine if the batch can be released for commercial sale. The thickness of the enteric coating is a key factor that determines the release rate of the drug in the gastro-intestinal tract. Also, the amount of drug per unit mass decreases with increasing thickness of the enteric coating. In this study, the coating process is tracked from start to finish on an hourly basis by taking samples of pellets during production and testing those using BARDS (Broadband Acoustic Resonance Dissolution Spectroscopy). BARDS offers a rapid approach to characterising enteric coatings with measurements based on reproducible changes in the compressibility of a solvent due to the evolution of air during dissolution. This is monitored Acoustically via associated changes in the frequency of induced Acoustic Resonances. A steady state Acoustic lag time is associated with the disintegration of the enteric coatings in basic solution. This lag time is pH dependent and is indicative of the rate at which the coating layer dissolves. BARDS represents a possible future surrogate test for conventional USP dissolution testing as its data correlates directly with the thickness of the enteric coating, its integrity and also with the drug loading as validated by HPLC.
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new insights into the mechanism of rehydration of milk protein concentrate powders determined by broadband Acoustic Resonance dissolution spectroscopy bards
Food Hydrocolloids, 2016Co-Authors: Bastiaan Vos, Jacob Kruse, Dara Fitzpatrick, Sean Mcsweeney, Shane V Crowley, Jonathan J Osullivan, Rachel Evanshurson, Rizwan M Ahmed, James A OmahonyAbstract:Abstract This study investigated the transfer of water into milk protein concentrate (MPC) powder particles using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) as a detection method for the first time. BARDS analysis is based on an Acoustic phenomenon which occurs during powder rehydration. Release of air from the powder into the solvent during rehydration leads to outgassing in the solvent, which results in changes in solvent compressibility that are monitored through accompanying changes in induced Resonance frequencies in the dissolution vessel. BARDS confirmed that water transfer into MPC particles became increasingly inhibited as protein content of the powder increased. The reproducibility of the data indicates that air release from internal vacuoles within powder particles in high-protein MPCs is a highly ordered process, occurring over a protracted time scale. Kinetic modelling of gas volume data from BARDS confirmed that the release of occluded air caused the changes in solvent compressibility during rehydration. The physicochemical properties of solubilised protein had a slight inhibitory effect on escape of bubbles from the solvent, but the primary factor limiting gas release from high-protein MPCs was water transfer into powder particles and the concomitant release of occluded air into the solvent. In agreement with many previous studies, cryo-SEM analysis showed that particles in high-protein MPCs were slow to disperse; the current study, in addition, highlights inhibited water transfer into particles as another factor which may contribute to their poor rehydration properties. A potential link between inhibited water transfer and poor dispersibility is proposed.
Sean Mcsweeney - One of the best experts on this subject based on the ideXlab platform.
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tracking yeast metabolism and the crabtree effect in real time via co2 production using broadband Acoustic Resonance dissolution spectroscopy bards
Journal of Biotechnology, 2020Co-Authors: Rizwan M Ahmed, Jacob Kruse, Sean Mcsweeney, Nicholas Doyle, Cathal Connolly, John P Morrissey, Michael B Prentice, Dara FitzpatrickAbstract:Abstract In this study, a new approach to measure metabolic activity of yeast via the Crabtree effect is described. BARDS is an analytical technique developed to aid powder and tablet characterisation by monitoring changes in the compressibility of a solvent during solute dissolution. It is a rapid and simple method which utilises a magnetic stir bar to mix added solute and induce the Acoustic Resonance of a vessel containing a fixed volume of solvent. In this study it is shown that initiation of fermentation in a yeast suspension, in aqueous buffer, is accompanied by reproducible changes in the frequency of induced Acoustic Resonance. These changes signify increased compressibility of the suspension due to CO2 release by the yeast. A simple standardised BARDS protocol reveals yeast carbon source preferences and can generate quantitative kinetic data on carbon source metabolism which are characteristic of each yeast strain. The Crawford-Woods equation can be used to quantify total gaseous CO2 produced by a given number of viable yeast when supplied with a fixed amount of carbon source. This allows for a value to be calculated for the amount of gaseous CO2 produced by each yeast cell. The approach has the potential to transform the way in which yeast metabolism is tracked and potentially provide an orthogonal or surrogate method to determining viability, vitality and attenuation measurements in the future.
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broadband Acoustic Resonance dissolution spectroscopy bards a rapid test for enteric coating thickness and integrity of controlled release pellet formulations
International Journal of Pharmaceutics, 2018Co-Authors: Anas Alfarsi, Amy Dillon, Jacob Kruse, Ken J Devine, Patricia Sherry, Stephan Henken, Brendan T Griffin, Sean Mcsweeney, Stephen Fitzpatrick, Dara FitzpatrickAbstract:Abstract There are no rapid dissolution based tests for determining coating thickness, integrity and drug concentration in controlled release pellets either during production or post-production. The manufacture of pellets requires several coating steps depending on the formulation. The sub-coating and enteric coating steps typically take up to six hours each followed by additional drying steps. Post production regulatory dissolution testing also takes up to six hours to determine if the batch can be released for commercial sale. The thickness of the enteric coating is a key factor that determines the release rate of the drug in the gastro-intestinal tract. Also, the amount of drug per unit mass decreases with increasing thickness of the enteric coating. In this study, the coating process is tracked from start to finish on an hourly basis by taking samples of pellets during production and testing those using BARDS (Broadband Acoustic Resonance Dissolution Spectroscopy). BARDS offers a rapid approach to characterising enteric coatings with measurements based on reproducible changes in the compressibility of a solvent due to the evolution of air during dissolution. This is monitored Acoustically via associated changes in the frequency of induced Acoustic Resonances. A steady state Acoustic lag time is associated with the disintegration of the enteric coatings in basic solution. This lag time is pH dependent and is indicative of the rate at which the coating layer dissolves. BARDS represents a possible future surrogate test for conventional USP dissolution testing as its data correlates directly with the thickness of the enteric coating, its integrity and also with the drug loading as validated by HPLC.
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new insights into the mechanism of rehydration of milk protein concentrate powders determined by broadband Acoustic Resonance dissolution spectroscopy bards
Food Hydrocolloids, 2016Co-Authors: Bastiaan Vos, Jacob Kruse, Dara Fitzpatrick, Sean Mcsweeney, Shane V Crowley, Jonathan J Osullivan, Rachel Evanshurson, Rizwan M Ahmed, James A OmahonyAbstract:Abstract This study investigated the transfer of water into milk protein concentrate (MPC) powder particles using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) as a detection method for the first time. BARDS analysis is based on an Acoustic phenomenon which occurs during powder rehydration. Release of air from the powder into the solvent during rehydration leads to outgassing in the solvent, which results in changes in solvent compressibility that are monitored through accompanying changes in induced Resonance frequencies in the dissolution vessel. BARDS confirmed that water transfer into MPC particles became increasingly inhibited as protein content of the powder increased. The reproducibility of the data indicates that air release from internal vacuoles within powder particles in high-protein MPCs is a highly ordered process, occurring over a protracted time scale. Kinetic modelling of gas volume data from BARDS confirmed that the release of occluded air caused the changes in solvent compressibility during rehydration. The physicochemical properties of solubilised protein had a slight inhibitory effect on escape of bubbles from the solvent, but the primary factor limiting gas release from high-protein MPCs was water transfer into powder particles and the concomitant release of occluded air into the solvent. In agreement with many previous studies, cryo-SEM analysis showed that particles in high-protein MPCs were slow to disperse; the current study, in addition, highlights inhibited water transfer into particles as another factor which may contribute to their poor rehydration properties. A potential link between inhibited water transfer and poor dispersibility is proposed.
Anas Alfarsi - One of the best experts on this subject based on the ideXlab platform.
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broadband Acoustic Resonance dissolution spectroscopy bards a rapid test for enteric coating thickness and integrity of controlled release pellet formulations
International Journal of Pharmaceutics, 2018Co-Authors: Anas Alfarsi, Amy Dillon, Jacob Kruse, Ken J Devine, Patricia Sherry, Stephan Henken, Brendan T Griffin, Sean Mcsweeney, Stephen Fitzpatrick, Dara FitzpatrickAbstract:Abstract There are no rapid dissolution based tests for determining coating thickness, integrity and drug concentration in controlled release pellets either during production or post-production. The manufacture of pellets requires several coating steps depending on the formulation. The sub-coating and enteric coating steps typically take up to six hours each followed by additional drying steps. Post production regulatory dissolution testing also takes up to six hours to determine if the batch can be released for commercial sale. The thickness of the enteric coating is a key factor that determines the release rate of the drug in the gastro-intestinal tract. Also, the amount of drug per unit mass decreases with increasing thickness of the enteric coating. In this study, the coating process is tracked from start to finish on an hourly basis by taking samples of pellets during production and testing those using BARDS (Broadband Acoustic Resonance Dissolution Spectroscopy). BARDS offers a rapid approach to characterising enteric coatings with measurements based on reproducible changes in the compressibility of a solvent due to the evolution of air during dissolution. This is monitored Acoustically via associated changes in the frequency of induced Acoustic Resonances. A steady state Acoustic lag time is associated with the disintegration of the enteric coatings in basic solution. This lag time is pH dependent and is indicative of the rate at which the coating layer dissolves. BARDS represents a possible future surrogate test for conventional USP dissolution testing as its data correlates directly with the thickness of the enteric coating, its integrity and also with the drug loading as validated by HPLC.
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Tracking Cocrystallization of Active Pharmaceutical Ingredients with Benzoic Acid Coformer Using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS)
2018Co-Authors: Christopher Kent, Anas Alfarsi, U. Rao B. Khandavilli, Melissa Hanna-brown, Seán Mcsweeney, Jacob Krüse, Simon Lawrence, Dara FitzpatrickAbstract:This study investigates the use of Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) as a detection method for the formation of cocrystals. BARDS is a novel approach that uses reproducible changes in the compressibility of a solvent as a sample dissolves to characterize and differentiate between materials and in this case cocrystallization. Two cocrystal systems with a 1:1 stoichiometry were examined, which used benzoic acid as a coformer with isonicotinamide and with theophylline. Cocrystals were prepared using dry and wet milling for periods from 1 to 40 min, and samples were analyzed using infrared spectroscopy, powder X-ray diffraction, and BARDS. Comparison of the BARDS data with the IR and PXRD data cross-validated the BARDS results. This study shows that BARDS can be used to rapidly assess the formation of these cocrystals at-line when milling or as a relatively low cost tool in preformulation product development. The data can also be used to gauge the unique entrained gas and gas volume generation of the cocrystal samples during dissolution and their dissolution kinetics
