3-(Phenyl-4-oxy)-5-phenyl-4,5-dihydro-(1 H )-pyrazole: A fascinating molecular framework to study the enantioseparation ability of the amylose (3,5-dimethylphenylcarbamate) chiral stationary phase. Part II. Solvophobic effects in enantiorecognition process

Pierini, Marco; Carradori, Simone; Menta, Sergio; Secci, Daniela; Cirilli, Roberto

doi:10.1016/j.chroma.2017.04.001

Cited by 24 publications

(15 citation statements)

References 12 publications

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“…The reasons for such uncommon retentive behavior under methanol mode are unclear. It has already been reported that methanol can produce a stronger retention than ethanol due to its capability to promote solvophobic interactions between the CSP and chiral analytes [7] and/or induce conformational changes in the helical structure of the polysaccharide selectors [8] , which can result in a higher affinity for selectands.…”

Section: Resultsmentioning

confidence: 99%

Unusual retention behavior of omeprazole and its chiral impurities B and E on the amylose tris (3-chloro-5-methylphenylcarbamate) chiral stationary phase in polar organic mode

Ferretti

Zanitti

Casulli

et al. 2018

Journal of Pharmaceutical Analysis

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Recent reports have demonstrated that the new commercially available immobilized-type chiral stationary phases (CSPs) containing amylose tris(3-chloro-5-methylphenylcarbamate) (ACMPC) as a selector exhibit not only an exceptionally high enantioselectivity in high-performance liquid chromatography (HPLC) but they are also applicable to a wide range of chiral analytes. Herein, we report the results obtained in the HPLC analysis of omeprazole and its impurities B and E on the ACMPC-based Chiralpak IG-3 CSP (CSP) under polar organic conditions. A systematic evaluation of the retention characteristics of the selected benzimidazole chiral probes was carried out by changing the composition of the mobile phase and the column temperature. It is worth emphasizing that the high affinity of both enantiomers of all analytes recorded in pure methanol mode dramatically decreased incorporating small volumes of either basic or acid additives in the mobile phase. Unspecified sites of the IG-3 CSP presumably involved in strong and non-stereoselective H-bonding contacts with chiral analytes are assumed responsible for the unproductive retention process.

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Section: Resultsmentioning

confidence: 99%

Unusual retention behavior of omeprazole and its chiral impurities B and E on the amylose tris (3-chloro-5-methylphenylcarbamate) chiral stationary phase in polar organic mode

Ferretti

Zanitti

Casulli

et al. 2018

Journal of Pharmaceutical Analysis

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“…This assumption appears to be confirmed by the fact that using different n ‐pentane/MeOH mixtures as eluents the competitive interaction is strengthened and shape of the retention graphs becomes concave (Fig. ) .…”

Section: Resultsmentioning

confidence: 68%

Development of a high‐performance liquid chromatography method for the simultaneous determination of chiral impurities and assay of (S)‐clopidogrel using a cellulose‐based chiral stationary phase in methanol/water mode

Ferretti

Zanitti

Cirilli

2018

J of Separation Science

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A simple reversed-phase high-performance liquid chromatography method for the chiral separation of the active pharmaceutical ingredient (S)-clopidogrel has been developed on the cellulose-based Chiralcel OJ-RH chiral stationary phase. The S enantiomer was baseline resolved from its R impurity (impurity C) with a mobile phase consisting of methanol/water (100:15) without any interference coming from the other two potential chiral impurities A and B. The enantio- and chemoselective method was partially validated and compared with that reported in the United States Pharmacopoeia for the drug product. The versatility of the Chiralcel OJ-RH allowed separating the enantiomers of the impurity B also under normal phase and setting up an efficient strategy to convert the racemic sample into the enantiomeric S form on a semipreparative scale.

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“…In several earlier studies, apart from H‐bonds, the importance of π‐π interactions between the selector and selectand were highlighted based on chromatographic data obtained for structurally similar analytes, while later, further insights were provided using complementary techniques on HPLC data, IR data, and molecular simulations . Moreover, in their recent reports, Cirilli et al highlighted the importance of uncommon solvophobic interactions in explaining the exceptionally high enantioselectivity values obtained for 3‐(phenyl‐4‐oxy)‐5‐phenyl‐4,5‐dihydro‐(1H)‐pyrazole, further underlining the importance of interactions between apolar portions of the selector and selectand amplified under polar organic conditions …”

Section: Resultsmentioning

confidence: 99%

“…[21][22][23] Moreover, in their recent reports, Cirilli et al highlighted the importance of uncommon solvophobic interactions in explaining the exceptionally high enantioselectivity values obtained for 3-(phenyl-4-oxy)-5-phenyl-4,5-dihydro-(1H)-pyrazole, further underlining the importance of interactions between apolar portions of the selector and selectand amplified under polar organic conditions. 24,25 Also, on most of the employed CSPs, there is no linear correlation between the polarity of the mobile phase and retention times of the analytes. As the polarity of the linear alcohols decreases in the order MeOH > EtOH > PrOH, an increase in analyte retention would be expected with the increase in alcohol chain length.…”

Section: Csp and Mobile Phase Screeningmentioning

confidence: 99%

Enantioseparation of racecadotril using polysaccharide‐type chiral stationary phases in polar organic mode

et al. 2017

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Enantioseparation of the antidiarrheal drug, racecadotril, was investigated by liquid chromatography using polysaccharide-type chiral stationary phases in polar organic mode. The enantiodiscrimininating properties of 4 different chiral columns (Chiralpak AD, Chiralcel OD, Chiralpak AS, Chiralcel OJ) with 5 different solvents (methanol, ethanol, 1-propanol, 2-propanol, and acetonitrile) at 5 different temperatures (5-40°C) were investigated. Apart from Chiralpak AS column the other 3 columns showed significant enantioseparation capabilities.Among the tested mobile phases, alcohol type solvents were superior over acetonitrile, and significant differences in enantioselective performance of the selector were observed depending on the type of alcohol employed. Van't Hoff analysis was used for calculation of thermodynamic parameters which revealed that enantioseparation is mainly enthalpy controlled; however, enthropic control was also observed. Enantiopure standard was used to determine the enantiomer elution order, revealing chiral selector-and mobile-phase dependent reversal of enantiomer elution order. Using the optimized method (Chiralcel OJ stationary phase, thermostated at 10°C, 100% methanol, flow rate: 0.6 mL/min) baseline separation of racecadotril enantiomers (resolution = 3.00 ± 0.02) was achieved, with the R-enantiomer eluting first. The method was validated according to the ICH guidelines, and its application was tested on capsule and granules containing the racemic mixture of the drug.

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3-(Phenyl-4-oxy)-5-phenyl-4,5-dihydro-(1 H )-pyrazole: A fascinating molecular framework to study the enantioseparation ability of the amylose (3,5-dimethylphenylcarbamate) chiral stationary phase. Part II. Solvophobic effects in enantiorecognition process

Cited by 24 publications

References 12 publications

Unusual retention behavior of omeprazole and its chiral impurities B and E on the amylose tris (3-chloro-5-methylphenylcarbamate) chiral stationary phase in polar organic mode

Unusual retention behavior of omeprazole and its chiral impurities B and E on the amylose tris (3-chloro-5-methylphenylcarbamate) chiral stationary phase in polar organic mode

Development of a high‐performance liquid chromatography method for the simultaneous determination of chiral impurities and assay of (S)‐clopidogrel using a cellulose‐based chiral stationary phase in methanol/water mode

Enantioseparation of racecadotril using polysaccharide‐type chiral stationary phases in polar organic mode

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