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1.
Enantiomeric resolution of some imidazole antifungal agents on chiralpak WH chiral stationary phase using HPLC 总被引:1,自引:0,他引:1
Summary The enantiomeric resolution of (±)-econazole, (±)-miconazole and (±)-sulconazole was achieved on a Chiralpak WH column. The
mobile phase used was hexane-2-propanol-diethylamine (400:99:1,v/v/v). The flow rates of the mobile phase used were 0.50 and 1.00 mL min−1. The values of α of the resolved enantiomers of econazole, miconazole and sulconazole were in the range of 1.68 to 1.23 while
the values of Rs varied from 2.42 to 1.10. The resolution of these antifungal agents on Chiralpak WH column is governed by
ligand exchange mechanism. Hydrophobic interactions also play an important role for the enantiomeric resoltuion of antifungal
agents on the reported CSP. 相似文献
2.
Summary A reversed-phase high-performance liquid chromatographic (HPLC) assay, based on the indirect approach to enantiomeric analysis,
for the determination of ibuprofen in human serum and urine has been developed. Following the addition of (R,S)-flurbiprofen, as internal standard, the enantiomers of ibuprofen were isolated from plasma and urine samples by liquid-liquid
extraction at acidic pH. The enantiomers of flurbiprofen and ibuprofen were derivatized with (R)-1-(naphthen-1-yl)ethylamine, using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 1-hydroxybenzotriazole as coupling
reagents, to yield the corresponding diastereoisomeric amides. Chromatographic resolution of the derivatives was achieved
using a C18 column (Waters Resolve C18; 5 μm, 150×3.9 mm) using a mobile phase of phosphate buffer (pH 3.5, 0.01 M): acetonitrile (50∶50 v/v) at a flow rate of
1.5 mL min−1 at ambient temperature. Quantification was carried out using a spectrofluorometer with excitation and emission wavelengths
of 290 and 330 nm respectively. The use of a semimicrobore column (150×2.1 mm) containing the same stationary phase facilitated
the analysis of the free drug enantiomer concentrations following equilibrium dialysis. The derivatization procedure was carried
out as described above but with a reduction in the quantities of the reagents used in order to reduce the background noise
in the chromatographic analysis. The HPLC methodology for the determination of free drug enantiomer concentrations was validated
against a previously reported method employing the radiolabelled drug. 相似文献
3.
A simple, isocratic, normal phase chiral HPLC method was developed and validated for the enantiomeric separation of repaglinide,
(S)-(+)-2-ethoxy-4-N [1-(2-piperidinophenyl)-3-methyl-1-butyl] aminocarbonylmethyl] benzoic acid, an antidiabetic in bulk drug substance. The
enantiomers of repaglinide were resolved on a ChiralPak AD-H (amylose based stationary phase) column using a mobile phase
consisting of n-hexane: 2-propanol:trifluoroacetic acid (95:5:0.2 v/v/v) at a flow rate of 1.0 mL min−1. The resolution between the enantiomers was found to be not >3.5 in optimized method. The presence of trifluoroacetic acid
in the mobile phase played an important role, in enhancing chromatographic efficiency and resolution between the enantiomers.
The developed method was extensively validated and proved to be robust. The calibration curve for (R)-enantiomer showed excellent linearity over the concentration range of 900 ng mL−1 (LOQ) to 6,000 ng mL−1. The limit of detection and limit of quantification for (R)-enantiomer were 300 and 900 ng mL−1, respectively. The percentage recovery of the (R)-enantiomer ranged between 98.3 and 101.05% in bulk drug samples of repaglinide. Repaglinide sample solution and mobile phase
were found to be stable up to 48 h. The developed method was found to be enantioselective, accurate, precise and suitable
for quantitative determination of (R)-enantiomer in bulk drug substance. 相似文献
4.
Summary A very simple non-aqueous reversed-phase HPLC method has been developed for analysis of retinol acetate, retinol palmitate,
cholecalciferol, α-tocopherol acetate and alphacalcidol in capsules without the need for saponification. A reversed-phase
(LiChrospher C8, 4.6 mm i.d.) column is used with acetonitrile-methanol, 95∶5 (v/v) as mobile phase at flow rate of 1 mL min−1. Sample treatment consists only in dilution of the capsule contents withn-hexane and methanol. This method is suitable for routine quantification in the industrial quality-assurance laboratory. 相似文献
5.
Summary A sensitive and selective high-performance liquid chromatographic method has been developed for monitoring clozapine levels
in human plasma. Chromatography was performed on a reversed-phase column (C8, 150 mm×4.6 mm i.d., 5 μm) with acetonitrile-aqueous sodium acetate solution, 88∶12 (v/v), as mobile phase; the flow rate was 1 mL min−1. Clozapine oxidation at +800 mV was detected amperometrically. Response was linearly dependent on concentration over the
range 50–1500 ng mL−1 clozapine in plasma. Sample preparation by solid-phase extraction before HPLC analysis gave high extraction yield (94%).
The accuracy and precision of the method were both very good (recovery: 97%;RSD<3.3%). 相似文献
6.
Simplified liquid-chromatographic determination of residues of tetracycline antibiotics in eggs 总被引:2,自引:0,他引:2
N. Furusawa 《Chromatographia》2001,53(1-2):47-50
Summary A high-performance liquid chromatographic (HPLC) procedure is described for the identification and quantification of residues
of tetracycline antibiotics (TCA) (oxytetracycline, tetracycline, chlortetracycline, and doxycycline), in eggs. Spiked and
blank samples were prepared by homogenization with 1∶1 (v/v) acetonitrile-mixed Mcllvaine buffer and EDTA solution (pH 4.0) then centrifugal ultrafiltration. HPLC was performed on a
reversed-phase column with acetonitrile-5% (v/v) aqueous acetic acid, 35∶65 (v/v), as mobile phase and photo-diode array detection. Average recoveries (each drug spiked at 0.1, 0.2, 0.3, 0.5 and 1.0 μg
g−1) were >-77% with standard deviations (SD) between 1.5 and 3.5%. The inter-assay variabilities and theirSD were <3.4% and <0.7%, respectively, and intra-assay variability was between 2.0 and 3.9%. The limits of quantitation (LOQ) were 0.064 0.087, 0.121, and 0.131 μg g−1 for OTC, TC, CTC, and DC, respectively. The total time required for the analysis of one sample was less than 30 min. 相似文献
7.
Summary Direct chiral-phase HPLC methods have been developed for the determination of flurbiprofen and its major metabolites, namely
4′-hydroxyflurbiprofen and 3′-hydroxy-4′-methoxyflurbiprofen, in biological fluids using a derivatized amylose chiral stationary
phase (CSP; Chiral-pak AD). Quantification of all three analytes, both free and conjugated, in urine was carried out following
liquid-liquid extraction using tandem ultraviolet (UV) and fluorescence detection. Determination of flurbiprofen and the 4′-hydroxy-metabolite
in plasma utilized the same CSP but required modification in the mobile phase composition and sole use of fluorescence detection.
The urine assay was linear (r>0.998) between 0.05–10 μg mL−1, 0.1–20 μg mL−1 and 0.01–2 μg mL−1 for the enantiomers of flurbiprofen, 4′-hydroxyflurbiprofen and 3′-hydroxy-4′-methoxyflurbiprofen respectively. The plasma
assay was linear (r>0.997) between 0.1–6 μg mL−1 and 0.01–0.6 μg mL−1 for the enantiomers of flurbiprofen and 4′-hydroxyflurbiprofen respectively. Both assays, typically yielded within- and between-day
imprecision and accuracy values less than 10% for the enantiomers of the different analytes. Initial volunteer studies suggest
that the disposition of flurbiprofen displays modest enantioselectivity in humans. 相似文献
8.
Summary The chromatographic separation and resolution of the enantiomers of flurbiprofen and its two major metabolites, 4′-hydroxyflurbiprofen
and 3′-hydroxy-4′-methoxyflurbiprofen was investigated using four different approaches: reversed-phase HPLC after pre-column
derivatization with (R)-1-(naphthen-1-yl)ethylamine; reversed-phase HPLC using hydroxypropyl-β-cyclodextrin as a chiral mobile phase additive; chiral-phase
HPLC using either an α1-acid glycoprotein CSP (Chiral-AGP) or an amylose tris(3,5-dimethylphenylcarbamate) CSP (Chiralpak AD). Of all the approaches,
only the direct method using the Chiralpak AD CSP demonstrated separation and enantiomeric resolution of all three analytes
within an acceptable run time of 45 minutes. Enantiomeric resolution values of 1.67,3.67 and 3.44 were obtained for flurbiprofen,
4′-hydroxyflurbiprofen and 3′-hydroxy-4′-methoxyflurbiprofen respectively. Semi-preparative isolation of the individual enantiomers
of both metabolites, followed by CD analysis, revealed that the elution order on the AD CSP wasR-beforeS-enantiomer for both metabolites and the same as that observed for flurbiprofen. The metabolite elution order was subsequently
confirmed on the analysis of urine samples obtained from a healthy volunteer following oral administration of the individual
drug enantiomers. 相似文献
9.
A simple liquid chromatographic method was developed for the separation and quantification of voriconazole and its enantiomer
in drug substance. The separation was achieved on Chiral cel-OD (250 mm × 4.6 mm × 10 μm) using mobile phase consisting of
n-hexane and ethanol in the ratio 9:1 (v/v) with a flow rate of 1.0 mL min−1, at 27 °C column temperature and detection at 254 nm with an injection volume of 20 μL. Ethanol was used as diluent. The
method is capable of detecting the (2S, 3R) enantiomer down to 0.0075% and can quantify down to 0.021% with respect to sample concentration. The method is rapid and
the resolution achieved was about 3.0. This method can be employed for the quantification of (2S, 3R) enantiomer in voriconazole drug substance. 相似文献
10.
P. Madhavan Bandlamudi Mallikarjuna Rao B. Pravin S. Abhishek P. R. Kumar M. Sreenivasulu K. B. Chandrasekhar 《Chromatographia》2007,66(3-4):243-246
A chiral liquid chromatographic method for enantiomeric resolution of β-amino-β-(3-methoxyphenyl) propionic acid was developed
and validated. The “hybrid” π-electron donor–acceptor based stationary phase (R,R) Whelk-01 was found to be enantiomerically
selective for (R) and (S) enantiomers of β-amino-β-(3-methoxyphenyl) propionic acid with a resolution greater than 2.0. The effects of isopropyl alcohol
and ethanol on enantioselectivity and resolution of enantiomers were evaluated. Calibration curves were linear over the range
of 0.10–1.00, with a regression coefficient (r) of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were 300 and 1,000 ng mL−1 respectively for 10 μL injection volume. The percentage RSD of the peak area of six replicate injections of (S) enantiomer at LOQ concentration was 2.8. The percentage recovery of (S) enantiomer from (R) enantiomer samples ranged from 92 to 102. The test solution was observed to be stable up to 24 h after the preparation.
The developed normal phase chiral LC method can be used for the enantiomeric purity evaluation of R-β-amino-β-(3-methoxyphenyl) propionic acid. 相似文献
11.
Summary A simple, sensitive, selective and robust isocratic LC method is described for the analysis of erythromycin on XTerra RP18. The main component, erythromycin A, is separated from all known related substances and degradation products. Several unknown
impurities are also separated. Acetonitrile-0.2 MK2HPO4pH7.0-water, (35∶5∶60, v/v) was used as a mobile phase at 1.0 mL min−1. UV detection was at 215 nm. The robustness of the method was evaluated by a full-factorial experimental design. 相似文献
12.
Summary An improved LC method is described for the separation of oxytetracycline and its impurities. The separation is much better
than that obtained with official pharmacopoeia methods. The method uses XTerra RP-18, 5 μm (25cm×4.6 mm I.D.), a silica-based
stationary phase with methyl end-capping, claimed to reduce silanol activity. The column temperature is set at 30°C and a
UV detection is performed at 280 nm. Mobile phase containing acetonitrile −0.25 M tetrabutylammonium hydrogen sulfate pH 7.5−0.25
M ethylenediaminetetraacetic acid pH 7.5-water (115:360:160:365,v/v/v/v) is used at a flow rate of 1.0 mL.min−1, to separate the impurities present in oxytetracycline base. A central composite experimental design is used to optimize
the separation. A second isocratic method with higher content of acetonitrile is needed to separate the more retained impurities
present only in oxytetracycline hydrochloride. The method is robust and shows good selectivity, repeatability, linearity and
sensitivity. 相似文献
13.
Marcelo Donadel Malesuik Simone Gonçalves Cardoso Martin Steppe 《Chromatographia》2008,67(1-2):131-136
A reversed-phase liquid chromatographic (LC) method was developed for the assay of nitazoxanide (NTZ) in solid dosage formulations.
An isocratic LC separation was performed on a Phenomenex Synergi Fusion C18 column (250 mm × 4.6 mm, i.d., 4 μm particle size) using a mobile phase of 0.1% o-phosphoric acid solution, pH 6.0: acetonitrile (45:55, v/v) at a flow rate of 1.0 mL min−1. Detection was achieved with a photodiode array detector at 240 nm. The detector response for NTZ was linear over the concentration
range from 2 to 100 μg mL−1 (r = 0.9999). The specificity and stability-indicating capability of the method were proved using stress conditions. The RSD
values for intra-day precision were less than 1.0% for tablets and powder for oral suspension. The RSD values for inter-day
precision were 0.6 and 0.7% for tablets and powder for oral suspension. The accuracy was 100.4% (RSD = 1.8%) for tablets and
100.9% (RSD = 0.3%) for powder for oral suspension. The limits of quantitation and detection were 0.4 and 0.1 μg mL−1. There was no interference of the excipients on the determination of the active pharmaceutical ingredient. The proposed method
was precise, accurate, specific, and sensitive. It can be applied to the quantitative determination of drug in tablets and
powder for oral suspension. 相似文献
14.
Summary A simple and sensitive isocratic LC method is described for the determination of erythromycins in fermentation broths. A simple
technique utilizing acetone-methyl ethyl ketone, 1∶1, as extraction solvent was coupled with suitable chromatographic conditions—compounds
were separated on a 250 mm×4.6 mm i.d., 5 μm, reversed-phase column at 65°C with acetonitrile-0.2m K2HPO4 pH7.0-water, 35:5:60 (v/v), as mobile phase at a flow rate of 1.0 mL min−1. UV detection was performed at 215 nm. Separation of erythromycin F from polar components of the fermentation liquid was
sufficient. Erythromycins A, B, C, D, and E, andN-desmethylerythromycin A were also separated, as were known decomposition products of erythromycin A and several unknown components.
The method is suitable for monitoring the progress of erythromycin fermentation. 相似文献
15.
A stability-indicating HPLC assay method was developed for the quantitative determination of tadalafil in bulk samples and
in pharmaceutical dosage forms in the presence of the degradation products. It involved a 250 mm × 4.6 mm, 5 μm C-18 column.
The gradient LC method employs solution A and B as mobile phase. Solution A contains a mixture of buffer (phosphate buffer
and tetra-n-butyl ammonium hydrogen sulfate) pH 2.5: acetonitrile (80:20, v/v) and solution B contains a mixture of water: acetonitrile (20:80, v/v). The flow rate was 1.0 mL min−1 and the detection wavelength was 220 nm. The retention time of tadalafil is about 17 min. Tadalafil was subjected to different
ICH prescribed stress conditions. Degradation was found to occur in hydrolytic and to some extent in oxidative stress conditions,
while the drug was stable to photolytic and thermal stress. The drug was particularly labile under alkaline hydrolytic conditions.
The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The assay of stress
samples was calculated against a qualified reference standard and the mass balance was close to 99.5%. The developed RP-LC
method was validated with respect to linearity, accuracy, precision and ruggedness. 相似文献
16.
Summary Momordicoside A has been determined by solid-phase extraction (SPE) on a Envi Carb cartridge (3 mL, 250mg) then high-performance
liquid chromatography (HPLC) on a C18 column (4.6 mm×250 mm, 5 μm particle) with acetonitrile-methanol-50mm potassium dihydrogen phosphate buffer, 25:20:60 (v/v), as mobile phase, at a flow rate of 0.8 mL min−1, and UV detection at 208 nm. The analytical method was shown to be highly reproducible, with precision (asRSD) and accuracy (asRME)<10%, both intra-day and inter-day. Absolute recoveries were >90%. The method was applied to the determination of momordicoside
A in various tissues from different varieties of bitter melon from different producing areas. 相似文献
17.
Summary A sensitive HPLC method with marbofloxacin (MAR) as internal standard and fluorescence detection is described for the analysis
of ofloxacin (OFL) enantiomers in plasma samples. Plasma samples were prepared by adding phosphate buffer (pH 7.4, 0.1m), then extracted with trichloromethane.S-OFL,R-OFL, and the internal standard were separated on a reversed-phase column with water-methanol, 85.5∶14.5, as mobile phase.
The concentrations ofS-OFL andR-OFL eluting from the column (retention times 7.5 and 8.7 min, respectively) were monitored by fluorescence detection withλ
ex = 331 andλ
em = 488 nm. The detection and quantitation limits were 10 and 20 ng mL−1, respectively, forS-OFL and 11 and 21 ng mL−1 forR-OFL. Response was linearly related to concentration in the range 10 to 2500 ng mL−1. Recovery was close to 93% for both compounds. The method was applied to determination of the enantiomers of OFL in plasma
samples collected during pharmacokinetic studies. 相似文献
18.
Mohammed A. Abounassif Mohammed M. Hefnawy Gamal A. E. Mostafa 《Monatshefte für Chemie / Chemical Monthly》2012,73(Z1):365-371
Abstract
A stereoselective HPLC method has been developed for the simultaneous determination of oxprenolol enantiomers in urine and pharmaceutical products. Enantiomeric resolution of oxprenolol was achieved on cellulose tris(3,5-dichlorophenylcarbamate) immobilized onto a 5 μm spherical porous silica chiral stationary phase (CSP) known as Chiralpak IC with UV detection at 273 nm. The mobile phase consisted of n-hexane:isopropanol:triethylamine 70:30:0.1 (v/v/v) at a flow rate of 1.0 cm3/min. The method was validated for its linearity, accuracy, precision, and robustness. The calibration curves were linear over the range of 0.5–75 μg/cm3, with a detection limit of 0.1 μg/cm3 for each enantiomer. An average recovery of 99.0% and a mean relative standard deviation of 2.6% at 40.0 μg/cm3 for S-(−)- and R-(+)-enantiomers were obtained. The overall recoveries of oxprenolol enantiomers from pharmaceutical formulations were in the range 97.5–99.0%, with RSDs ranging from 0.6 to 0.8%. The mean extraction efficiency of oxprenolol from urine was in the range of 86.0–93.0% at 0.5–5 μg/cm3 for each enantiomer. The assay method proved to be suitable as a chiral quality control for oxprenolol formulations using HPLC and for therapeutic drug monitoring. 相似文献19.
The direct enantioseparation of duloxetine and its R-enantiomer was achieved by HPLC using hydroxypropyl-β-cyclodextrin (HP-β-CD) as a chiral selector and a vancomycin chiral
stationary phase (Chirobiotic V). Operational parameters, such as the concentration of HP-β-CD, buffer pH, organic modifiers,
temperature and flow rate, were varied in order to achieve the desired retention time and resolution. These two enantioseparation
methods developed gave a baseline resolution of the enantiomers. Finally, the HPLC-CSP method was selected to determine the
enantiomeric purity of duloxetine drug substance due to its much shorter analysis time and better resolution. The limit of
detection of this method was 0.06 μg mL−1. 相似文献
20.
Basma Saleh Tongyan Ding Yuwei Wang Xiantong Zheng Rong Liu Limin He 《Molecules (Basel, Switzerland)》2021,26(23)
Closantel is an antiparasitic drug marketed in a racemic form with one chiral center. It is meaningful to develop a method for separating and analyzing the closantel enantiomers. In this work, two enantiomeric separation methods of closantel were explored by normal-phase high-performance liquid chromatography. The influences of the chiral stationary phase (CSP) structure, the mobile phase composition, the nature and proportion of different mobile phase modifiers (alcohols and acids), and the column temperature on the enantiomeric separation of closantel were investigated in detail. The two enantiomers were successfully separated on the novel CSP of isopropyl derivatives of cyclofructan 6 and n-hexane-isopropanol-trifluoroacetic acid (97:3:0.1, v/v/v) as a mobile phase with a resolution (Rs) of about 2.48. The enantiomers were also well separated on the CSP of tris-carbamates of amylose with a higher Rs (about 3.79) when a mixture of n-hexane-isopropanol-trifluoroacetic acid (55:45:0.1, v/v/v) was used as mobile phase. Thus, the proposed separation methods can facilitate molecular pharmacological and biological research on closantel and its enantiomers. 相似文献