Chiralpak IC Column Research Articles

Enantioselective separation and determination of miconazole in rat plasma by chiral LC-MS/MS: application in a stereoselective pharmacokinetic study.

Miconazole has one chiral center, and consists of two enantiomers. In this study, a novel chiral liquid chromatography-tandem mass spectrometry method was developed for enantioselective separation and determination of miconazole in rat plasma. For the first time, the enantioselective pharmacokinetics of miconazole was investigated by the current method. Firstly, attempts were made to separate the enantiomers in reversed-phase mode with a mobile phase that was mass spectrometry compatible. Baseline separation was achieved on a Chiralpak IC column with a mobile phase composed of acetonitrile and aqueous ammonium hydrogen carbonate (5mM; 80:20, v/v). Data were acquired in multiple reaction monitoring mode with positive electrospray ionization by triple-quadrupole mass spectrometry. Then, overall method validation regarding the linearity, accuracy, precision, extraction recovery, matrix effect, and stability of each enantiomer was performed, and acceptable results were obtained for all of these. Finally, the method developed was applied in an enantioselective pharmacokinetic study of miconazole enantiomers in rats after oral administration of racemic miconazole at doses of 5 and 10mg/kg. The results demonstrated that (-)-(R)-miconazole had a higher concentration than (+)-(S)-miconazole in plasma, with a ratio of 1.3-1.7 for both doses. This is the first experimental evidence of enantioselective behavior of miconazole in vivo, and provides a reference for clinical practice and encourages further research into miconazole enantioselective metabolism and drug interactions. Graphical Abstract A stereoselective pharmacokinetic study of the miconazole enantiomers was investigated using a novel chiral liquid chromatography-tandem mass spectrometry method. Baseline separation was achieved on Chiralpak IC column, and Chiralcel OJ column was used to collect single enantiomer. A significant difference between the two enantiomers was observed in view of the plasma concentration.

Enantiomerization and stereoselectivity in bioaccumulation of furalaxyl in Tenebrio molitor larvae

Furalaxyl is a chiral pesticide and widely used in modern agriculture as racemate mixture. The enantiomerization and enantioselecive bioaccumulation by a single dose of furalaxyl to Tenebrio molitor larvae under laboratory conditions were studied using a high-performance liquid chromatography tandem mass spectroscopy method based on a ChiralPAK IC column. Our results showed that a significant enantiomerization (interconversion between R-enantiomer and S-enantiomer) was observed in Tenebrio molitor larvae under R- or S-furalaxyl exposure. Though the two furalaxyl enantiomers exhibited low-capacity of bioaccumulation in Tenebrio molitor larvae, bioaccumulation of rac-furalaxyl was enantioselective with a preferential accumulation of S-furalaxyl at 10mg/kg dosage exposure. In addition, enantiomerization and enantioselective degradation of the two enantiomers was not observed in wheat bran. These results showed that enantioselectivtiy of furalaxyl enantiomers was an important process combined with degradation, metabolism and enatiomerization in organisms.

Determination of rabeprazole enantiomers in commercial tablets using immobilized cellulose-based stationary phase.

Rabeprazole is one of the latest proton-pump inhibitors used for treatment of several gastrointestinal disorders. For therapeutic applications, rabeprazole has been administered as a mixture of R-(+) and S-(-) enantiomers. Owing to pharmacological and toxicological differences between stereoisomers, chiral recognition has now become an integral part of drug research and development. A simple and rapid liquid chromatographic method for enantioselective separation and determination of R-(+) and S-(-) enantiomers of rabeprazole in bulk drug and pharmaceutical formulations was developed. Chiralpak IC (150×4.6mm, 5μm) column and μmobile phase containing hexane:ethanol:ethylenediamine (30:70:0.05 v/v) in an isocratic mode yielded baseline separation with resolution greater than 6.0 at 35°C. Effects of additives and n-hexane were evaluated. Optimized condition was validated as per ICH guidelines. The method has good linearity, high sensitivity with LOD was 0.01μg/mL and LOQ was 0.03μg/mL for both enantiomers. Intra-day precision varied between 0.44 and 1.79% for S-(-) enantiomer, 0.65 and 1.97% for R-(+) enantiomer. Relative standard deviations of inter-day precision were less than 1.81% for both enantiomers. The percentage recovery for both enantiomers of rabeprazole ranged between 99.81 and 101.95%, 98.82 and 101.36% in material and tablets, respectively. The method was successfully applied to determine content of each enantiomer in commercial tablets.

고성능 액체 크로마토그래피에 의한 다당 유도체의 키랄 고정상에서 플록세틴의 새롭게 개발된 분석 및 반분취의 광학분리

A liquid chromatographic method for the enantiomer separation of fluoxetine was performed using covalently bonded and coated type polysaccharide-derived chiral stationary phases (CSPs). The degree of enantioseparation is affected by the used CSPs and mobile phases. The performance of Chiralpak IC was superior to the other CSPs used in this study. Out of various solvent composition and additives, the greatest separation and resolution was observed using Chiralpak IC with mobile phase of 2-propanol in hexane with diethylamine as an additive. Semi-preparative separation of fluoxetine was performed on the analytical Chiralpak IC column to obtain (R)- and (S)-fluoxetine enantiomer with high chemical and optical purity. From the overall study, the developed liquid chromatographic method on polysaccharide-derived CSPs is expected to be very useful for the enantiomer separation of fluoxetine.

Development and Validation of Chiral HPLC Method for Quantification of 3-(S)-Quinuclidinol in Pharmaceutically Important Precursor, 3-(R)-Quinuclidinol, by Precolumn Derivatization.

A sensitive and specific high-performance liquid chromatography (HPLC) method for the separation and quantification of 3-(S)-quinuclidinol in 3-(R)-quinuclidinol, precursor for active pharmaceutical ingredients (solifenacin, revatropate and talsaclidine), has been developed and validated by precolumn derivatization. Several chiral columns were tested in a normal phase system. Excellent enantioseparation with the resolution more than 11.4 was achieved on Chiralpak IC column using isocratic mobile phase consisting of n-hexane, ethanol, 2-propanol and diethylamine (80:8:12:0.4, v/v). The detection was carried out using UV detector at 230 nm. The influence of mobile phase composition, namely organic modifiers, additives, aliphatic alkanes and water content in mobile phase, on retention and enantioseparation was studied. Validation of the developed method including specificity, system suitability, limit of detection, limit of quantification, linearity, repeatability, intermediate precision, accuracy and solution stability was performed according to the International Conference on Harmonization guidelines. The advantage of the method is a good HPLC enantioseparation by precolumn derivatization using reaction mixture as sample, simpler UV detection, short analysis time (<30 min), and therefore this method is suitable option for routine quantification of 3-(S)-quinuclidinol in 3-(R)-quinuclidinol.

Solid-phase extraction combined with dispersive liquid-liquid microextraction and chiral liquid chromatography-tandem mass spectrometry for the simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

This report describes, for the first time, the simultaneous enantioselective determination of proton-pump inhibitors (PPIs-omeprazole, lansoprazole, pantoprazole, and rabeprazole) in environmental water matrices based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and chiral liquid chromatography-tandem mass spectrometry. The optimized results of SPE-DLLME were obtained with PEP-2 column using methanol-acetonitrile (1/1, v/v) as elution solvent, dichloroethane, and acetonitrile as extractant and disperser solvent, respectively. The separation and determination were performed using reversed-phase chromatography on a cellulose chiral stationary phase, a Chiralpak IC (250mm × 4.6mm, 5μm) column, under isocratic conditions at 0.6mLmin(-1) flow rate. The analytes were detected in multiple reaction monitoring (MRM) mode by triple quadrupole mass spectrometry. Isotopically labeled internal standards were used to compensate matrix interferences. The method provided enrichment factors of around 500. Under optimal conditions, the mean recoveries for all eight enantiomers from the water samples were 89.3-107.3% with 0.9-10.3% intra-day RSD and 2.3-8.1% inter-day RSD at 20 and 100ngL(-1) levels. Correlation coefficients (r (2)) ≥ 0.999 were achieved for all enantiomers within the range of 2-500μgL(-1). The method detection and quantification limits were at very low levels, within the range of 0.67-2.29ngL(-1) and 2.54-8.68ngL(-1), respectively. This method was successfully applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in wastewater and river water, making it applicable to the assessment of the enantiomeric fate of PPIs in the environment. Graphical Abstract Simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

Improved Chiral Separation of (R,S)-Goitrin by SFC: An Application in Traditional Chinese Medicine

Like chemical drugs, research and development of herbal medicine also have a need to resolve enantiomers. To help illustrating the antiviral bioactivity of Isatidis Radix, a widely used traditional Chinese medicine (TCM), supercritical fluid chromatography (SFC) was used for analytical and preparative separation of (R,S)-goitrin, which was reported as the active ingredient of the herbal. Improved resolution was achieved on Chiralpak IC column, using acetonitrile as the organic modifier, representing a tenfold increase in speed, compared to the previous normal phase HPLC (NPLC) method. The newly developed chromatographic method was validated in terms of linearity, precision, limit of detection (LOD), and limit of quantitation (LOQ). Scale-up purification of (R)-goitrin and (S)-goitrin was performed on a preparative column with >90% total recovery. The absolute stereochemical assignment of the purified isomers was determined through optical rotation study. This attempt explored SFC's application in chiral research of traditional Chinese medicine.

Enantioselective determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with mass spectrometry and its application to a stereoselective pharmacokinetic study.

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with tandem mass spectrometry. Lansoprazole enantiomers and internal standard (esomeprazole) were extracted from plasma using acetonitrile as protein precipitating agent. Baseline chiral separation was achieved within 9.0 min on a Chiralpak IC column (150 mm × 4.6 mm, 5 μm) with the column temperature of 30°C. The mobile phase consisted of 10 mM ammonium acetate solution containing 0.05% acetic acid/acetonitrile (50:50, v/v). The mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. The multiple reactions monitoring transitions of m/z 370.1→252.1 and 346.1→198.1 were used to quantify lansoprazole enantiomers and esomeprazole, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00-3000 ng/mL, the intra- and inter-day precisions were below 10.0%, and the accuracy was -3.8 to 3.3%. Analytes were stable during the study. No chiral inversion was observed during sample storage, preparation procedure and analysis. The method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of dexlansoprazole or racemic lansoprazole.

Determination of the Enantiomerization Barrier of the Residual Enantiomers of C3 -Symmetric Tris[3-(1-Methyl-2-Alkyl)Indolyl]Phosphane Oxides: Case Study of a Multitasking HPLC Investigation Based on an Immobilized Polysaccharide Stationary Phase.

The residual enantiomers of three tris-(3-indolyl)-phosphane oxides bearing different alkyl groups (methyl, ethyl or i-propyl) in position 2 of the indole rings constituting the blades were separated on the immobilized type Chiralpak IC column in polar organic and reversed-phase modes. The good enantioselectivity and versatility of the IC CSP allowed easy isolation of the enantiomerically highly enriched samples suitable for configurational stability studies. The enantiomerization barriers of residual phosphane oxides were evaluated both by off-column techniques (CD signal and enantiomeric purity decay kinetics) and by dynamic enantioselective high-performance liquid chromatography (HPLC).

Enantioselective degradation of indoxacarb from different commercial formulations applied to tea.

The stereoselective degradation of indoxacarb enriched with (+)-S-indoxacarb (S/R:70/30) was investigated in three typical green teas. A convenient and precise chiral method was developed and validated for measuring indoxacarb enantiomers in green tea. The developed method was based on high-performance liquid chromatography coupled with tandem mass spectrometry using a Chiralpak IC column. The stereoselective degradation of indoxacarb enantiomers showed that the (+)-S-enantiomer dissipated faster than the (-)-R-enantiomer in all three typical tea farms. However, no enantiomerization was observed after applying pure (+)-S-indoxacarb. Residues on tea plant of the active ingredient (+)-S-indoxacarb from suspension concentrate (SC) was more persistent than that from emulsifiable concentrate (EC).

A Validated Chiral Liquid Chromatographic Method for the Enantiomeric Separation of Lacosamide Drug Product and its Dosage Forms

A new and simple, rapid, selective isocratic normal phase liquid chromatographic (NP-LC) method was developed for the chiral purity of Lacosamide ((R)-2-acetamido-N-benzyl-3- methoxypropionamide) and its undesired S-enantiomer ((S)-2-acetamido-N-benzyl-3-methoxypropionamide). Superior resolution between Lacosamide and its S-enantiomer was achieved on Cellulose tris (3,5-Dichlorophenylcarbamate) immobilisation of polysaccharide derivatives based Chiralpak IC (25 mm × 4.6 mm, 5 μm) column using n-hexane : ethanol (85:15, v/v) as a mobile phase at 27°C column oven temperature. The USP resolution between the enantiomers was found more than five. Mobile phase flow was fixed at a rate of 1.0 mL/min and elution was monitored at 210 nm. The test concentration was 1000 μg/ml, Limit of detection and quantitative of S-enantiomer is 0.17 μg/mL and 0.48 μg/mL respectively. The percentage RSD of the peak area of six replicate injections of S-enantiomer at LOQ concentration was 5.8. The percentage recoveries of S-enantiomer from Lacosamide (LAC) were ranged from 105%-107%. The test solution and mobile phase were observed to be stable up to 48 h on bench top. The method was found to be selective, precise, linear, accurate and also robust. This method was successfully validated according to the International Conference Harmonization (ICH) guidelines.

Detection of Xeljanz enantiomers in diethyl amine active pharmaceutical ingredients and tablets.

A high-performance liquid chromatography (HPLC) method was established to detect Xeljanz enantiomers in active pharmaceutical ingredients (APIs) and tablets. The separation was achieved on a Chiralpak IC column using a mobile phase of hexane-ethanol-diethylamine (65:35:0.1, v/v). The detection wavelength was 289 nm. The peak areas and the enantiomer concentrations in the range of 0.15-2.25 μg•mL(-1) were in high linearity, with correlation coefficients higher than 0.999. The recoveries were 86.44% at the concentrations of 7.5, 18.75, and 37.5 μg•mL(-1) . The limit of detection (LOD) and limit of quantification (LOQ) were 0.042 and 0.14 μg•mL(-1) , respectively. This HPLC method is suitable for detecting the enantiomers of Xeljanz in its APIs and tablets.

Thermodynamic evaluation of immobilized cellulose tris(3,5-dichlorophenylcarbamate) as a stationary phase for liquid chromatographic separation of darunavir enantiomers.

Liquid chromatographic separation of darunavir (DRV) enantiomers was studied on Chiralpak IC column containing immobilized cellulose tris(3,5-dichlorophenylcarbamate) using a variety of mobile phase solvents at different temperatures. The separations were accomplished under normal phase conditions using different compositions of n-hexane, organic modifier (2-propanol, ethanol or 1-propanol) and diethyl amine (0.1%) as mobile phase solvents. The effect of volume and nature of organic modifier and column temperature on retention, separation and resolution were studied. Van't Hoff plots (ln k' vs 1/T) were drawn from the chromatographic retention data to calculate to apparent thermodynamic parameters and explain the interactions between the DRV enantiomers and cellulose tris(3,5-dichlorophenylcarbamate) immobilized on silica.

The Chiral Separation and Enantioselective Degradation of the Chiral Herbicide Napropamide

The chiral pesticide enantiomers often have different toxic effects and environmental behaviors, which suggests that the risk assessments should be on an enantiomeric level. In this work, the chiral separation of the napropamide enantiomers and the stereoselective degradation in tomato, cucumber, rape, cabbage, and soil were investigated. Napropamide enantiomers could be separated absolutely by high-performance liquid chromatography (HPLC) using a Chiralpak IC column with a resolution factor of 11.75 under the optimized condition. Solid phase extraction (SPE) was used for cleanup of the enantiomers in the vegetable samples. The residue analysis method was validated. Good linearities (R(2) = 0.9997) and recoveries (71.43% -97.64%) were obtained. The limits of detection (LOD) were 0.05 mg/kg in soil and 0.20 mg/kg in vegetables. The results of degradation showed that napropamide dissipated rapidly in vegetables with half-lives of only 1.13-2.21 days, but much more slowly in soil, with a half-life of 11.95 d. Slight stereoselective degradation of the two enantiomers was only observed in cabbage, with enantiomeric fraction (EF) = 0.46, and there was no enantioselectivity in the other vegetables. The degradation of napropamide in the five matrixes was fast, and there was no enantioselectivity.

Chiral separation of six tetralone derivative enantiomers using immobilized cellulose chiral stationary phase

A high performance liquid chromatographic method (HPLC) was developed for the chiral separation of six α-aryl tetralone derivatives, using a Chiralpak IC column. The factors influencing the chiral separation including the type and concentration of organic modifier, column temperature and flow rate were investigated. The results showed that high enantiomeric separation can be obtained with isopropanol as modifier for the six compounds. The thermodynamic study indicated that the enantioseparation was enthalpically driven and showed that low column temperature was beneficial to separation. Complete separation of compound I was achieved with a binary solvent mixture of n-hexane-isopropanol (90 :10, v/v) as the recommended mobile phase. The compounds II , II and IV were separated with the mobile phase of the mixture of n-hexane-isopropanol (99:1, v/v) and the compound V was separated with the mixture of n-hexane-isopropanol (85:15, v/v). The compound VI was separated with the mixture of n-hexane-isopropanol (80:20, v/v). The column temperature was 25 °C, and the flow rate was 1. 0 mL/min. The six tetralone derivative enantiomers were separated on a chiral stationary phase of Chiralpak IC by HPLC. The column has high enantiomeric selectivity to the six tetralone derivative enantiomers.

A New Chiral Residue Analysis Method for Triazole Fungicides in Water Using Dispersive Liquid‐Liquid Microextraction (DLLME)

A rapid, simple, reliable, and environment-friendly method for the residue analysis of the enantiomers of four chiral fungicides including hexaconazole, triadimefon, tebuconazole, and penconazole in water samples was developed by dispersive liquid-liquid microextraction (DLLME) pretreatment followed by chiral high-performance liquid chromatography (HPLC)-DAD detection. The enantiomers were separated on a Chiralpak IC column by HPLC applying n-hexane or petroleum ether as mobile phase and ethanol or isopropanol as modifier. The influences of mobile phase composition and temperature on the resolution were investigated and most of the enantiomers could be completely separated in 20 min under optimized conditions. The thermodynamic parameters indicated that the separation was enthalpy-driven. The elution orders were detected by both circular dichroism detector (CD) and optical rotatory dispersion detector (ORD). Parameters affecting the DLLME performance for pretreatment of the chiral fungicides residue in water samples, such as the extraction and dispersive solvents and their volume, were studied and optimized. Under the optimum microextraction condition the enrichment factors were over 121 and the linearities were 30-1500 µg L(-1) with the correlation coefficients (R(2)) over 0.9988 and the recoveries were between 88.7% and 103.7% at the spiking levels of 0.5, 0.25, and 0.05 mg L(-1) (for each enantiomer) with relative standard deviations varying from 1.38% to 6.70% (n = 6) The limits of detection (LODs) ranged from 8.5 to 29.0 µg L(-1) (S/N = 3).

Absolute Configuration and Enantiodifferentiation of a Hemicryptophane Incorporating an Azaphosphatrane Moiety

The hemicryptophane racemate (±)-1 was optically resolved by semipreparative HPLC on Chiralpak IC column. The absolute configuration of each isolated enantiomer was established from the analysis of their electronic circular dichroism spectra. Enantiodifferentiation of the chiral cationic cage (±)-1 was evidenced in solution using Δ-TRISPHAT as chiral solvating agent, and the diastereomeric associations were observed in (1)H and (31)P NMR spectra.

Enantioseparation of 1-Phenyl-1,2,3,4-tetrahydroisoquinoline on Polysaccharide-Based Chiral Stationary Phases

The enantiomers of 1-phenyl-1,2,3,4-tetrahydroisoquinoline have been directly separated on polysaccharide-based chiral stationary phases (CSPs). The normal phase separation of (S)- and (R)-1-phenyl-1,2,3,4-tetrahydroisoquinoline was accomplished by screening of the immobilized Chiralpak IC column with different eluents. The effect of mobile phase type on retention, selectivity and resolution was studied. 2-Propanol or ethanol/n-hexane/ethanolamine mixtures were applied as mobile phases by screening of following polysaccharide-based immobilized (Chiralpak IA, Chiralpak IC) and coated (Lux Cellulose-1, Lux Cellulose-2, Lux Amylose-2) CSPs. Polar organic and reversed-phase conditions were also tested for direct enantioseparation of 1-phenyl-1,2,3,4-tetrahydroisoquinoline.

Development and Validation of New Chromatographic Method for the Determination of Enantiomeric and Diastereomeric Purity of Solifenacin Succinate: An Antimuscarinic Agent

A new, simple, and rapid stereoselective normal phase-liquid chromatographic (NP-LC) method was developed to separate and quantify the solifenacin succinate and its three stereoisomers. The stereoisomeric separation was achieved on Chiralpak IC ( mm ID) column. The mobile phase was consisting of n-hexane, ethanol, isopropyl alcohol, and diethylamine in the ratio (60 : 15 : 25 : 0.1, v/v/v/v), and the flow rate was maintained at 1.0 mL min−1. UV detection was carried out at 220 nm. In addition, chiroptical detection was carried out using laser polarimeter to understand the elution orders. Resolution between all the stereoisomers was not less than 3. Effect of column temperature on resolution between the stereoisomers was studied. The method was validated as per ICH guideline and found to be robust. The proposed NP-LC method was successfully applied to the analysis of commercial formulation. The method could be of use not only for routine evaluation of the quality of solifenacin succinate in bulk drug manufacturing unit but also for detection of impurities in pharmaceutical formulations.

Perfluorooctane Sulfonate (PFOS) Precursors Can Be Metabolized Enantioselectively: Principle for a New PFOS Source Tracking Tool

Perfluorooctane sulfonate (PFOS) is the most prominent perfluoroalkyl substance found in the serum of humans and wildlife, yet the major routes by which exposure occurs are not clear. An important issue facing both the scientific and chemical regulatory communities is the extent to which PFOS concentrations in biota are attributable to direct exposure versus metabolism of PFOS-precursors (higher molecular weight derivatives that can be biotransformed to PFOS). Given that certain branched PFOS-precursors are chiral, we hypothesized that nonracemic proportions of PFOS isomers in biological samples could be used as a marker of significant exposure to PFOS-precursors. In this proof-of-principle study we examined the enantiomer-specific biotransformation of a high-purity model PFOS-precursor isomer: C(6)F(13)C*F(CF(3))SO(2)N(H)CH(2)(C(6)H(4))OCH(3) (named 1m-PreFOS hereafter, and whereby * indicates the chiral carbon center). A method for the enantiospecific separation of a compound with a long perfluoroalkyl chain and a chiral center was developed and applied to evaluate the enantioselectivity of 1m-PreFOS biotransformation in human liver microsomes. Gradient elution in reversed-phase mode on a Chiralpak IC column permitted the near-baseline separation of the two enantiomers (E1 and E2, nomenclature based on retention order) in 65 min. Microsome incubations demonstrated that E1 and E2 were metabolized at significantly different rates; k(E1) = 6.5(+/-0.3) x 10(-2) min(-1) (half-life = 10.6 min) and k(E2) = 5.2(+/-0.3) x 10(-2) min(-1) (half-life = 13.3 min), respectively. These results suggest that tracking of PFOS exposure sources by enantiomeric fractionation is feasible, and that new analytical methods for the enantioselective analysis of PFOS isomers in human and environmental samples should be developed.