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Papers by Hasret Ates
Journal of Pharmaceutical and Biomedical Analysis, 2008
Because of the large number of commercially available chiral selectors both for electrophoretic a... more Because of the large number of commercially available chiral selectors both for electrophoretic and chromatographic techniques, the experimental possibilities to separate enantiomers are numerous. As a result, the development of a proper separation method for a chiral molecule is challenging. Generic separation strategies can present a useful approach for chiral method development. This paper overviews some strategies that have been developed earlier for different electrophoretic and chromatographic techniques. These strategies can be used either for impurity determination of enantiomers or for the enantioseparation of racemic mixtures. They are not only generic, i.e. applicable on diverse molecules, but are also fast, i.e. requiring only a limited number of experiments to reach a decision.
Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2008
The screening conditions of an existing column and mobile phase selection strategy for chiral dru... more The screening conditions of an existing column and mobile phase selection strategy for chiral drug substances in polar organic solvent liquid chromatography (POSC) were tested for their applicability on two new chlorine-containing polysaccharide-based stationary phases. The selectors of these phases are cellulose tris(3-chloro-4-methylphenylcarbamate) and amylose tris(5-chloro-2-methylphenylcarbamate). The enantioselectivity of these phases is compared to that of the four phases (Chiralpak ® AD-RH, Chiralcel ® OD-RH, Chiralpak ® AS-RH and Chiralcel ® OJ-RH) used in the earlier defined strategy. A test set of 62 structurally diverse chiral drug substances is analyzed using the screening conditions of the strategy on the six phases. The results confirm that the acetonitrile-based mobile phase provides a higher success rate and better resolutions than the methanol-based also on the new phases. However, the importance of the methanol-based mobile phase cannot be neglected for complementarity reasons; the two mobile phases insure enantioselectivity for different compounds. A third (ethanol-based) mobile phase, not part of the strategy, was also used to screen the two new phases. The joint results led to different possibilities to upgrade the current screening strategy so that improved success rates are obtained. The chlorinecontaining chiral stationary phases demonstrated to have an added value to the screening process since they provided enantioresolution for compounds not resolved by non-chlorine-containing ones.
Journal of Pharmaceutical and Biomedical Analysis, 2008
Because of the large number of commercially available chiral selectors both for electrophoretic a... more Because of the large number of commercially available chiral selectors both for electrophoretic and chromatographic techniques, the experimental possibilities to separate enantiomers are numerous. As a result, the development of a proper separation method for a chiral molecule is challenging. Generic separation strategies can present a useful approach for chiral method development. This paper overviews some strategies that have been developed earlier for different electrophoretic and chromatographic techniques. These strategies can be used either for impurity determination of enantiomers or for the enantioseparation of racemic mixtures. They are not only generic, i.e. applicable on diverse molecules, but are also fast, i.e. requiring only a limited number of experiments to reach a decision.
Journal of Chromatography B-analytical Technologies in The Biomedical and Life Sciences, 2008
The screening conditions of an existing column and mobile phase selection strategy for chiral dru... more The screening conditions of an existing column and mobile phase selection strategy for chiral drug substances in polar organic solvent liquid chromatography (POSC) were tested for their applicability on two new chlorine-containing polysaccharide-based stationary phases. The selectors of these phases are cellulose tris(3-chloro-4-methylphenylcarbamate) and amylose tris(5-chloro-2-methylphenylcarbamate). The enantioselectivity of these phases is compared to that of the four phases (Chiralpak ® AD-RH, Chiralcel ® OD-RH, Chiralpak ® AS-RH and Chiralcel ® OJ-RH) used in the earlier defined strategy. A test set of 62 structurally diverse chiral drug substances is analyzed using the screening conditions of the strategy on the six phases. The results confirm that the acetonitrile-based mobile phase provides a higher success rate and better resolutions than the methanol-based also on the new phases. However, the importance of the methanol-based mobile phase cannot be neglected for complementarity reasons; the two mobile phases insure enantioselectivity for different compounds. A third (ethanol-based) mobile phase, not part of the strategy, was also used to screen the two new phases. The joint results led to different possibilities to upgrade the current screening strategy so that improved success rates are obtained. The chlorinecontaining chiral stationary phases demonstrated to have an added value to the screening process since they provided enantioresolution for compounds not resolved by non-chlorine-containing ones.