The Experts below are selected from a list of 17511 Experts worldwide ranked by ideXlab platform
Paola Calza - One of the best experts on this subject based on the ideXlab platform.
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Identification of the unknown Transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high‐resolution mass spectrometry
Rapid communications in mass spectrometry : RCM, 2012Co-Authors: Paola Calza, Claudio Medana, Valeria Rachele Giancotti, E. Padovano, Claudio BaiocchiAbstract:RATIONALE A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high-resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study. METHODS The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ-Orbitrap analyzer. High-resolution mass spectrometry was employed to assess the evolution of the Drug Transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different Transformation products (TPs) and to distinguish the isobaric species. RESULTS The simulation of photoTransformation occurring in the aquatic environment and identification of biotic and abiotic Transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty-eight main species were identified after carbamazepine Transformation and twenty-nine for clarithromycin. CONCLUSIONS This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the Transformation pathways followed by the two Drugs. Copyright © 2012 John Wiley & Sons, Ltd.
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Characterization of phenazone Transformation products on light-activated TiO2 surface by high-resolution mass spectrometry.
Rapid communications in mass spectrometry : RCM, 2011Co-Authors: Paola Calza, Claudio Medana, E. Raso, Valeria Rachele Giancotti, C. MineroAbstract:The paper examines the Transformation of phenazone (2,3-dimethyl-1-phenyl-3-pyrazolin-5-one), a widely used analgesic and antipyretic Drug, under simulated solar irradiation in pure water, using titanium dioxide, and in river water. High-resolution mass spectrometry was employed to monitor the evolution of photoinduced processes. Initially, laboratory experiments were performed to simulate Drug-Transformation pathways in aqueous solution, using TiO(2) as photocatalyst. Thirteen main phenazone Transformation products were detected, and full analysis of their MS and MS(n) spectra identified the diverse isobaric species. All these Transformation products were themselves easily degraded, and no compounds were recognized to remain until 1h of irradiation. From these findings, a tentative degradation pathway is proposed to account for the photoinduced Transformation of phenazone in natural waters. These simulation experiments were verified in the field, seeking phenazone in River Po water samples.
Claudio Baiocchi - One of the best experts on this subject based on the ideXlab platform.
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Identification of the unknown Transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high‐resolution mass spectrometry
Rapid communications in mass spectrometry : RCM, 2012Co-Authors: Paola Calza, Claudio Medana, Valeria Rachele Giancotti, E. Padovano, Claudio BaiocchiAbstract:RATIONALE A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high-resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study. METHODS The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ-Orbitrap analyzer. High-resolution mass spectrometry was employed to assess the evolution of the Drug Transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different Transformation products (TPs) and to distinguish the isobaric species. RESULTS The simulation of photoTransformation occurring in the aquatic environment and identification of biotic and abiotic Transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty-eight main species were identified after carbamazepine Transformation and twenty-nine for clarithromycin. CONCLUSIONS This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the Transformation pathways followed by the two Drugs. Copyright © 2012 John Wiley & Sons, Ltd.
Valeria Rachele Giancotti - One of the best experts on this subject based on the ideXlab platform.
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Identification of the unknown Transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high‐resolution mass spectrometry
Rapid communications in mass spectrometry : RCM, 2012Co-Authors: Paola Calza, Claudio Medana, Valeria Rachele Giancotti, E. Padovano, Claudio BaiocchiAbstract:RATIONALE A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high-resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study. METHODS The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ-Orbitrap analyzer. High-resolution mass spectrometry was employed to assess the evolution of the Drug Transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different Transformation products (TPs) and to distinguish the isobaric species. RESULTS The simulation of photoTransformation occurring in the aquatic environment and identification of biotic and abiotic Transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty-eight main species were identified after carbamazepine Transformation and twenty-nine for clarithromycin. CONCLUSIONS This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the Transformation pathways followed by the two Drugs. Copyright © 2012 John Wiley & Sons, Ltd.
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Characterization of phenazone Transformation products on light-activated TiO2 surface by high-resolution mass spectrometry.
Rapid communications in mass spectrometry : RCM, 2011Co-Authors: Paola Calza, Claudio Medana, E. Raso, Valeria Rachele Giancotti, C. MineroAbstract:The paper examines the Transformation of phenazone (2,3-dimethyl-1-phenyl-3-pyrazolin-5-one), a widely used analgesic and antipyretic Drug, under simulated solar irradiation in pure water, using titanium dioxide, and in river water. High-resolution mass spectrometry was employed to monitor the evolution of photoinduced processes. Initially, laboratory experiments were performed to simulate Drug-Transformation pathways in aqueous solution, using TiO(2) as photocatalyst. Thirteen main phenazone Transformation products were detected, and full analysis of their MS and MS(n) spectra identified the diverse isobaric species. All these Transformation products were themselves easily degraded, and no compounds were recognized to remain until 1h of irradiation. From these findings, a tentative degradation pathway is proposed to account for the photoinduced Transformation of phenazone in natural waters. These simulation experiments were verified in the field, seeking phenazone in River Po water samples.
Claudio Medana - One of the best experts on this subject based on the ideXlab platform.
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Identification of the unknown Transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high‐resolution mass spectrometry
Rapid communications in mass spectrometry : RCM, 2012Co-Authors: Paola Calza, Claudio Medana, Valeria Rachele Giancotti, E. Padovano, Claudio BaiocchiAbstract:RATIONALE A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high-resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study. METHODS The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ-Orbitrap analyzer. High-resolution mass spectrometry was employed to assess the evolution of the Drug Transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different Transformation products (TPs) and to distinguish the isobaric species. RESULTS The simulation of photoTransformation occurring in the aquatic environment and identification of biotic and abiotic Transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty-eight main species were identified after carbamazepine Transformation and twenty-nine for clarithromycin. CONCLUSIONS This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the Transformation pathways followed by the two Drugs. Copyright © 2012 John Wiley & Sons, Ltd.
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Characterization of phenazone Transformation products on light-activated TiO2 surface by high-resolution mass spectrometry.
Rapid communications in mass spectrometry : RCM, 2011Co-Authors: Paola Calza, Claudio Medana, E. Raso, Valeria Rachele Giancotti, C. MineroAbstract:The paper examines the Transformation of phenazone (2,3-dimethyl-1-phenyl-3-pyrazolin-5-one), a widely used analgesic and antipyretic Drug, under simulated solar irradiation in pure water, using titanium dioxide, and in river water. High-resolution mass spectrometry was employed to monitor the evolution of photoinduced processes. Initially, laboratory experiments were performed to simulate Drug-Transformation pathways in aqueous solution, using TiO(2) as photocatalyst. Thirteen main phenazone Transformation products were detected, and full analysis of their MS and MS(n) spectra identified the diverse isobaric species. All these Transformation products were themselves easily degraded, and no compounds were recognized to remain until 1h of irradiation. From these findings, a tentative degradation pathway is proposed to account for the photoinduced Transformation of phenazone in natural waters. These simulation experiments were verified in the field, seeking phenazone in River Po water samples.
Jukka Rantanen - One of the best experts on this subject based on the ideXlab platform.
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Excipients‐Induced Salt‐to‐Free Base Phase Transformation
Chemical Engineering & Technology, 2013Co-Authors: Maria Cinta Roda Serrat, Lars Porskjær Christensen, Jukka RantanenAbstract:The mechanism of the salt-to-free form Drug Transformation was explored by investigating the pH-solubility profiles of a model Drug in a salt form and the nucleation of the free base from the salt solution when its pH was increasing. The Transformation of the salt to the free base during wet massing in the presence of pharmaceutical excipients with different pH was studied. The nucleation of the free base occurred when the pH of the salt solution reached a certain level pHmetastable, which was related to the free energy penalty associated with the creation of a new solid phase. The nucleation of the free base happened readily and thus, the salt-to-free base Transformation occurred rapidly during wet massing with the excipients with a pH above the pHmetastable. These results can support robust formulation design of solid dosage forms containing salts by optimal excipient selection.
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Process-induced phase Transformations in a pharmaceutically relevant salt-free form system
Chemical Engineering Science, 2012Co-Authors: Marja Savolainen, Lars Porskjær Christensen, Jukka RantanenAbstract:Salt formation is the most commonly used technique to improve the aqueous solubility and dissolution rate of active pharmaceutical ingredients. The phase Transformation of the salt to the free form of the Drug is extremely undesirable, since it will change the solubility and dissolution rate of the active substance and therefore alter the bioavailability of the final product. The mechanism of the salt-to-free form Drug Transformation was explored in the present work by investigating the pH-solubility profiles of the different solid forms (anhydrate, monohydrate and dihydrate) of the model Drug in a salt form (amlodipine besylate), the nucleation of the free base and the Transformation of the salt to the free base in aqueous suspensions in the presence of different pharmaceutical excipients. It has been observed that the nucleation of the free base occurred when the pH of the solution reached a certain level pHmetastable, which was related to the free energy penalty associated with the creation of a new interface. The Transformation behavior of the salt solid forms to the free base demonstrated that the nucleation of the free base was a decisive step in the phase Transformation. The nucleation of the free base happened readily and thus the salt-to-free base Transformation occurred rapidly in the excipient–salt suspension with a pH above the pHmetastable. On the other hand, the salt-to-free base Transformation was hindered in the excipient suspensions with a pH below the pHmetastable. The results of the present work can support robust formulation design of solid dosage forms containing salts by optimal excipient selection.
