RESUMEN
Chiral metal-organic frameworks(CMOFs)with enantiomeric subunits have been employed in chiral chemistry.In this study,a CMOF formed from 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid(HQA)and ZnCl2,{(HQA)(ZnCl2)(2.5H2O)｝n was constructed as a chiral stationary phase(CSP)via an in situ fabrication approach and used for chiral amino acid and drug analyses for the first time.The{(HQA)(ZnCl2)(2.5H2O)}n nanocrystal and the corresponding chiral stationary phase were systematically characterised using a series of analytical techniques including scanning electron microscopy,X-ray diffraction,Fourier transform infrared spectroscopy,circular dichroism,X-ray photoelectron spectros-copy,thermogravimetric analysis,and Brunauer-Emmett-Teller surface area measurements.In open-tubular capillary electrochromatography(CEC),the novel chiral column exhibited strong and broad enantioselectivity toward a variety of chiral analytes,including 19 racemic dansyl amino acids and several model chiral drugs(both acidic and basic).The chiral CEC conditions were optimised,and the enantioseparation mechanisms are discussed.This study not only introduces a new high-efficiency member of the MOF-type CSP family but also demonstrates the potential of improving the enantiose-lectivities of traditional chiral recognition reagents by fully using the inherent characteristics of porous organic frameworks.
RESUMEN
Homochiral metal-organic frameworks(MOFs)have attracted considerable attention in many fields of research,such as chiral catalysis and chiral chromatography.However,only few homochiral MOFs can be effectively used in capillary electrochromatography(CEC)and their performances are far from adequate.In this study,we successfully synthesized achiral nanocrystalline MIL-53.A facile post-synthetic modi-fication strategy was then implemented to functionalize the product,yielding a homochiral MOF:L-His-NH-MIL-53.This MOF was then employed as a chiral coating in open-tubular CEC mode(OT-CEC),and,as such,it exhibited high enantioselectivities for several racemic drugs.The homochiral MOF and the fabricated capillary coating were systematically characterized using transmission electron microscopy,scanning electron microscopy(with energy-dispersive X-ray spectrometry),Fourier-transform infrared spectroscopy,X-ray diffractometry,thermogravimetric analysis,circular dichroism spectroscopy,Bru-nauer-Emmett-Teller surface area measurements,and X-ray photoelectron spectroscopy.This study is expected to provide a new strategy for the design and establishment of MOF-based chiral OT-CEC systems.
RESUMEN
A 6-azido-β-cyclodextrin was synthesized and derivatized with p-nitrophenyl isocyanate as chiral ligand. Following that the ligand was chemically bonded to mesoporous SBA-15 via a ‘Click Chemistry ’ reaction of the azido group with alkynyl group. A new p-nitrophenylcarbamoylatedβ-cyclodextrin bonded SBA-15 chiral stationary phase ( NPCSP ) for HPLC was obtained. The new stationary phase was first used to enantioseparate propranolol in human plasma under the polar organic solvent mode. The effects of methanol content , additive concentration of glacial acetic acid/triethylamine in mobile phase and the temperature on the enantioseparation were studied. The optimal chromatographic conditions were as follows: mobile phase was acetonitrile/methanol/glacial acetic acid/triethylamine (90:10:1. 25:2. 25, V/V), temperature 288 K, flow rate of 0. 5 mL/min, injection volume of 20 μL, detection wavelength at 290 nm. The resolution was 2. 04 with a short run time (< 15 min) under the above conditions. The composition of propranolol in plasma was quantitatively measured by HPLC-MS selected ion monitoring mode ( [ M +H ]+ m/z 260 . 10 ) with hydrochlorothiazide as internal standard. And linear range was 2. 5-250 μg/L and with a good linear relationship. The detection limit was 1 μg/L according to S/N=3. The experimental results showed that the chiral stationary phase exhibited excellent chiral separation ability to propranolol and the analysis method for propranolol in plasma was sensitive, accurate, simple and fast, which could be used for the determination of propranolol in plasma and pharmacokinetic studies.
RESUMEN
OBJECTIVE: To establish a fast and efficient HPLC method for the chiral separation of ondansetron hydrochloride and determination of the enantiomic impurity of (-)ondansetron(R)hydrochloride.
RESUMEN
The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) methods,which included ibuprofen (Cl),ketoprofen (C2),nitrendipine (C3),nimodipine (C4),felodipine (C5),omeprazole (C6),praziquantel (C7),propranolol hydrochloride (C8),atenolol (C9),sulpiride (C10),clenbuterol hydrochloride (C11),verapamil hydrochloride (C12),and chlorphenamine maleate (C13).The mobile phase consisted of isopropanol and n-hexane.The detection wavelength was set at 254 nm and the flow rate was 0.7 mL/min.The enantiomers separation of these thirteen racemates on chiralpak OD column and chiralpak OJ column was studied,while the effects of proportion of organic additives,alcohol displacer and temperature on the separation were studied.And the mechanism of some of racemates was discussed.The results indicated that thirteen chiral drugs could be separated on chiral stationary phase of cellulose ramification in normal phase chromatographic system.The chromatographic retention and resolution of enantiomers could be adjusted by factors including column temperature and the concentration of alcohol displacer and organic alkaline modifier in mobile phase.It was shown that the resolution was improved with reducing concentration of alcohol displacer.When concentration of organic alkaline modifier was 0.2％ (v/v),the resolution and the peak shape were fairly good.Most racemates mentioned above had better resolution at column temperature of 25 ℃.When racemates were separated,the temperature should be kept so as to obtain stable separation results.
RESUMEN
A method for the rapid enantioseparation of five β-blocker drugs, including alprenolol, propranolol), mexiletine, metoprolol and pindolol was developed by a 5-cm short column packed with perphenylcarbamoylated β-cyclodextrin(CD) chiral stationary phase by HPLC. The results showed that except for alprenolol), the other 4 β-blocker drugs were completely separated using ACN-0.1% thriethylammonium acetate(TEAA), 40∶ 60, V/V, pH=4.0) as mobile phase. The 5-cm short CD-based column exhibited rapid separation ability to the above β-blocker drugs within 5 min, which indicated that the separation has high efficiency. According to the chemical structures of the β-blockers and their chromatographic behavior, related separation mechanisms were also discussed. The proposed method was rapid, effective and repeated.
RESUMEN
OBJECTIVE:To establish a HPLC-chiral stationary phase(CSP) for separating the enantiomers of lactic acid and determining the optical purity of lactic acid.METHODS:Lactic acid samples of different optical purity were determined by HPLC-CSP vs.optical rotation method.The enantiomers of lactic acid were separated on Chirex 3126(D)-penicillamine chiral column.The mobile phase consisted of copper sulfate solution-isopropyl alcohol (85∶15) at a flow rate of 0.6 mL?min-1.The detection wavelength was set at 254 nm.RESULTS:A baseline separation of the enantiomers of lactic acid was achieved with a separation factor of greater than 1.2.The calibration curve was linear in the range of 0.75～48.24 mg?mL-1 (r=0.999 3),RSD=1.21%.The determination results determined by HPLC-CSP were similar to those determined by optical rotation method.CONCLUSION:The established method is simple,reliable in results and reproducible,and it is applicable for the separation of the enantiomers of lactic acid and determination of the optical purity of lactic acid.
RESUMEN
OBJECTIVE:To establish an HPLC-CSP (chiral stationary phase) for the determination of plasma levels of enantiomers of fluoxetine. METHODS: Enantiomers of fluoxetine were separated on a Chirobiotic V column. The mobile phase consisted of methanol-acetic acid-triethylamine (100∶0.04∶0.04) with a flow rate of 1 mL?min-1. The detection wavelength was set at 226 nm.Clozapine was used as the internal standard. RESULTS: Under this chromatographic condition, both R-norfluoxetine and S-norfluoxetine had no interference on the enantiomers of fluoxetine and the internal standard. The calibration curve was linear in the range of 8.1～432 ng?mL-1(r=0.999 8) for R-enantiomer and in the range of 10.8～432 ng?mL-1 (r=0.999 2) for S-enantiomer. The relative recovery of R-fluoxetine and S-fluoxetine in plasma were 97.2%～101.9% and 98.7%～102.2%, respectively. RSD of intraday and interday ranged from 2.6% to 5.3% and from 7.7% to 8.9% for R-fluoxetine, and from 2.1% to 6.7% and from 8.0% to 10.6% for S-fuoxetine, respectively. CONCLUSION: The method is simple, reliable and sensitive, and applicable for the determination and pharmacokinetic study of the enantiomers of fluoxetine in plasma.