The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Bezhan Chankvetadze - One of the best experts on this subject based on the ideXlab platform.
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comparative enantioseparation of talinolol in Aqueous and non Aqueous capillary electrophoresis and study of related selector selectand interactions by nuclear magnetic resonance spectroscopy
Journal of Chromatography A, 2012Co-Authors: Lali Chankvetadze, Anne-catherine Servais, Marianne Fillet, Antonio Salgado, Jacques Crommen, Bezhan ChankvetadzeAbstract:Abstract The enantiomers of the chiral β-blocker drug talinolol were separated with two single component sulfated β-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-β-CD) (HDMS-β-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-β-CD) (HDAS-β-CD), in Aqueous and non-Aqueous capillary electrophoresis (CE). The enantiomer affinity pattern of talinolol toward these two CDs was opposite in both Aqueous and non-Aqueous CE. However, the enantiomer affinity pattern for a given CD derivative did not change when Aqueous buffer was replaced with non-Aqueous background electrolyte. The structures of the analyte–selector complexes in both, Aqueous and non-Aqueous electrolytes were studied using rotating frame nuclear Overhauser effect (ROESY) NMR spectroscopy. Inclusion complex formation between the enantiomers of talinolol and HDAS-β-CD was confirmed in Aqueous buffer, while the complex between the enantiomers of talinolol and HDMS-β-CD was of the external type. The complex of the talinolol enantiomers with HDAS-β-CD in non-Aqueous electrolyte was also of the external type. In spite of external complex formation excellent separation of the enantiomers was observed in non-Aqueous CE.
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Comparative enantioseparation of talinolol in Aqueous and non-Aqueous capillary electrophoresis and study of related selector–selectand interactions by nuclear magnetic resonance spectroscopy
Journal of chromatography. A, 2012Co-Authors: Lali Chankvetadze, Anne-catherine Servais, Marianne Fillet, Antonio Salgado, Jacques Crommen, Bezhan ChankvetadzeAbstract:Abstract The enantiomers of the chiral β-blocker drug talinolol were separated with two single component sulfated β-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-β-CD) (HDMS-β-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-β-CD) (HDAS-β-CD), in Aqueous and non-Aqueous capillary electrophoresis (CE). The enantiomer affinity pattern of talinolol toward these two CDs was opposite in both Aqueous and non-Aqueous CE. However, the enantiomer affinity pattern for a given CD derivative did not change when Aqueous buffer was replaced with non-Aqueous background electrolyte. The structures of the analyte–selector complexes in both, Aqueous and non-Aqueous electrolytes were studied using rotating frame nuclear Overhauser effect (ROESY) NMR spectroscopy. Inclusion complex formation between the enantiomers of talinolol and HDAS-β-CD was confirmed in Aqueous buffer, while the complex between the enantiomers of talinolol and HDMS-β-CD was of the external type. The complex of the talinolol enantiomers with HDAS-β-CD in non-Aqueous electrolyte was also of the external type. In spite of external complex formation excellent separation of the enantiomers was observed in non-Aqueous CE.
Esko Aine - One of the best experts on this subject based on the ideXlab platform.
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Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in Aqueous humor.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2008Co-Authors: Marjo Volotinen, Auli Ropo, Heikki Vapaatalo, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the Aqueous humor was 210+/-175 ng/ml (mean+/-S.D.) 2h after administration of timolol 0.1% hydrogel and 538+/-304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. beta(1)-receptors and beta(2)-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
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Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in Aqueous humor.
European Journal of Pharmaceutical Sciences, 2008Co-Authors: Marjo Volotinen, Auli Ropo, Heikki Vapaatalo, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Abstract Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the Aqueous humor was 210 ± 175 ng/ml (mean ± S.D.) 2 h after administration of timolol 0.1% hydrogel and 538 ± 304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. β 1 -receptors and β 2 -receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
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Ophthalmic timolol in a hydrogel vehicle leads to minor interindividual variation in timolol concentration in Aqueous humor
Acta Ophthalmologica, 2008Co-Authors: Heikki Vapaatalo, Auli Ropo, Marjo Volotinen, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Purpose Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. Results The concentration in the Aqueous humor was 210 ± 175 ng/ml (mean ± SD) two hours after administration of timolol 0.1% hydrogel and 538 ± 304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. Beta 1-receptors and Beta 2-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. A similar correlation was observed between age and concentration of timolol in the aqeuous 0.5% timolol group. Conclusion In contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
Laxmi Ananthanarayan - One of the best experts on this subject based on the ideXlab platform.
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enzyme stability and stabilization Aqueous and non Aqueous environment
Process Biochemistry, 2008Co-Authors: Padma V Iyer, Laxmi AnanthanarayanAbstract:Enzyme stabilization has notable importance due to increasing number of enzyme applications. Stabilization of enzymes in order to realize their full potential as catalysts is discussed in the present review. An overview of the denaturation mechanisms in Aqueous and non-Aqueous environment is given. Further various methods of enzyme stabilization with respect to their use in Aqueous and non-Aqueous environment have been given. Using thermophilic enzymes as the reference point, a review of stabilization using various approaches like protein engineering, chemical modifications of enzymes and immobilization has been attempted. Finally, it has been stressed that, for selection of a suitable stabilization approach the intended use and possible interactions between the stabilizer-enzyme have to be taken into consideration.
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Enzyme stability and stabilization—Aqueous and non-Aqueous environment
Process Biochemistry, 2008Co-Authors: Padma V Iyer, Laxmi AnanthanarayanAbstract:Enzyme stabilization has notable importance due to increasing number of enzyme applications. Stabilization of enzymes in order to realize their full potential as catalysts is discussed in the present review. An overview of the denaturation mechanisms in Aqueous and non-Aqueous environment is given. Further various methods of enzyme stabilization with respect to their use in Aqueous and non-Aqueous environment have been given. Using thermophilic enzymes as the reference point, a review of stabilization using various approaches like protein engineering, chemical modifications of enzymes and immobilization has been attempted. Finally, it has been stressed that, for selection of a suitable stabilization approach the intended use and possible interactions between the stabilizer-enzyme have to be taken into consideration.
Lali Chankvetadze - One of the best experts on this subject based on the ideXlab platform.
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comparative enantioseparation of talinolol in Aqueous and non Aqueous capillary electrophoresis and study of related selector selectand interactions by nuclear magnetic resonance spectroscopy
Journal of Chromatography A, 2012Co-Authors: Lali Chankvetadze, Anne-catherine Servais, Marianne Fillet, Antonio Salgado, Jacques Crommen, Bezhan ChankvetadzeAbstract:Abstract The enantiomers of the chiral β-blocker drug talinolol were separated with two single component sulfated β-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-β-CD) (HDMS-β-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-β-CD) (HDAS-β-CD), in Aqueous and non-Aqueous capillary electrophoresis (CE). The enantiomer affinity pattern of talinolol toward these two CDs was opposite in both Aqueous and non-Aqueous CE. However, the enantiomer affinity pattern for a given CD derivative did not change when Aqueous buffer was replaced with non-Aqueous background electrolyte. The structures of the analyte–selector complexes in both, Aqueous and non-Aqueous electrolytes were studied using rotating frame nuclear Overhauser effect (ROESY) NMR spectroscopy. Inclusion complex formation between the enantiomers of talinolol and HDAS-β-CD was confirmed in Aqueous buffer, while the complex between the enantiomers of talinolol and HDMS-β-CD was of the external type. The complex of the talinolol enantiomers with HDAS-β-CD in non-Aqueous electrolyte was also of the external type. In spite of external complex formation excellent separation of the enantiomers was observed in non-Aqueous CE.
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Comparative enantioseparation of talinolol in Aqueous and non-Aqueous capillary electrophoresis and study of related selector–selectand interactions by nuclear magnetic resonance spectroscopy
Journal of chromatography. A, 2012Co-Authors: Lali Chankvetadze, Anne-catherine Servais, Marianne Fillet, Antonio Salgado, Jacques Crommen, Bezhan ChankvetadzeAbstract:Abstract The enantiomers of the chiral β-blocker drug talinolol were separated with two single component sulfated β-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-β-CD) (HDMS-β-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-β-CD) (HDAS-β-CD), in Aqueous and non-Aqueous capillary electrophoresis (CE). The enantiomer affinity pattern of talinolol toward these two CDs was opposite in both Aqueous and non-Aqueous CE. However, the enantiomer affinity pattern for a given CD derivative did not change when Aqueous buffer was replaced with non-Aqueous background electrolyte. The structures of the analyte–selector complexes in both, Aqueous and non-Aqueous electrolytes were studied using rotating frame nuclear Overhauser effect (ROESY) NMR spectroscopy. Inclusion complex formation between the enantiomers of talinolol and HDAS-β-CD was confirmed in Aqueous buffer, while the complex between the enantiomers of talinolol and HDMS-β-CD was of the external type. The complex of the talinolol enantiomers with HDAS-β-CD in non-Aqueous electrolyte was also of the external type. In spite of external complex formation excellent separation of the enantiomers was observed in non-Aqueous CE.
Marjo Volotinen - One of the best experts on this subject based on the ideXlab platform.
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Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in Aqueous humor.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2008Co-Authors: Marjo Volotinen, Auli Ropo, Heikki Vapaatalo, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the Aqueous humor was 210+/-175 ng/ml (mean+/-S.D.) 2h after administration of timolol 0.1% hydrogel and 538+/-304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. beta(1)-receptors and beta(2)-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
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Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in Aqueous humor.
European Journal of Pharmaceutical Sciences, 2008Co-Authors: Marjo Volotinen, Auli Ropo, Heikki Vapaatalo, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Abstract Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the Aqueous humor was 210 ± 175 ng/ml (mean ± S.D.) 2 h after administration of timolol 0.1% hydrogel and 538 ± 304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. β 1 -receptors and β 2 -receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
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Ophthalmic timolol in a hydrogel vehicle leads to minor interindividual variation in timolol concentration in Aqueous humor
Acta Ophthalmologica, 2008Co-Authors: Heikki Vapaatalo, Auli Ropo, Marjo Volotinen, J Mäenpää, H Kautiainen, A Tolonen, J Uusitalo, Esko AineAbstract:Purpose Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in Aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare Aqueous humor timolol concentrations after administration of 0.1% hydrogel and Aqueous 0.5% timolol in patients scheduled for a cataract operation. Results The concentration in the Aqueous humor was 210 ± 175 ng/ml (mean ± SD) two hours after administration of timolol 0.1% hydrogel and 538 ± 304 ng/ml after Aqueous 0.5% timolol. In the Aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the Aqueous humor. Beta 1-receptors and Beta 2-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the Aqueous humor. Only a weak correlation was seen between corneal thickness and the Aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. A similar correlation was observed between age and concentration of timolol in the aqeuous 0.5% timolol group. Conclusion In contrast to the conventional Aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the Aqueous humor.
