Present High-performance Liquid Chromatography Method Research Articles

Chiral Separation of Econazole by High Performance Liquid Chromatography Method using Cyclodextrin as Chiral Column

The chiral separation of econazole, an antifungal drug with one chiral center has been successfully carried out using the high-performance liquid chromatography (HPLC) method. Enantioresolution of econazole (Rs = 2.29) was achieved using cyclodextrin-based chiral column (Astec Cyclobond, 25 cm × 4.6 mm × 5 μm), mobile phase composition of acetonitrile : water (0.2% HCOOH) (20:80, v/v), and UV detection of 220 nm.The optimized HPLC method has been applied for the quantitative determination of econazole in the pharmaceutical (liquid) sample withpercentage recovery of 100.75 % (RSD = 0,95%; n = 3). The effect of several HPLC parameters on the chiral separation of econazole was also evaluated and the method was successfully validated in terms of linearity, accuracy, precision, and selectivity. The present HPLC method was simple, short analysis time, and high resolution.

Emtricitabine, Tenofovir, and Rilpivirine from their degradation products Analysis by HPLC

A simple, expeditious, and explicit stability-indicating High-Performance Liquid Chromatography (HPLC) analytical test method was developed for the quantitative analysis of Emtricitabine, Tenofovir, and Rilpivirine in bulk drugs and combined dosage formulations. Using the ICH guidelines method was validated using a C18 column of size 250 mm X 4.6 mm, 5µ, maintained at 25oC. The total run time maintained was 10 min. Acetonitrile and 0.1% TEA prepared in water adjusted with pH 3.0 was adapted as a mobile phase. The injection volume of samples was 20μL and UV-DAD detector system set at 265 nm used for UV detection. As per the ICH guidelines method was validated. The retention times were observed as 2.52, 3.27, 6.70 min for Emtricitabine, Rilpivirine, and Tenofovir disoproxyl fumarate, respectively. Linearity ranges were observed 24-56 µg/mL Emtricitabine, 3-7 µg/mL Rilpivirine and 30-70 µg/mL Tenofovir. Relative Standard Deviation not exceed 2%. In contract to the conventional method of HPLC, a method developed was able to give better resolution of swift retention times in the separation of various degradation products along with the pure active pharmaceutical ingredients. The proposed method exhibited excellent reproducibility and repeatability. The stress studies performed by following ICH guidelines indicated that the present HPLC method is explicit and stability-indicating. Since the present HPLC method has the capacity to separate the drugs with high resolution in tablet dosage forms, hence the method can be exploited for routine analysis of quality control sample and stability analysis.

Enantiomeric resolution, thermodynamic parameters, and modeling of clausenamidone and neoclausenamidone on polysaccharide-based chiral stationary phases.

The aim of the paper is to describe a new synthesis route to obtain synthetic optically active clausenamidone and neoclausenamidone and then use high-performance liquid chromatography (HPLC) to determine the optical purities of these isomers. In the process, we investigated the different chromatographic conditions so as to provide the best separation method. At the same time, a thermodynamic study and molecular simulations were also carried out to validate the experimental results; a brief probe into the separation mechanism was also performed. Two chiral stationary phases (CSPs) were compared with separate the enantiomers. Elution was conducted in the organic mode with n-hexane and iso-propanol (IPA) (80/20v/v) as the mobile phases; the enantiomeric excess (ee) values of the synthetic R-clausenamidone and S-clausenamidone and R-neoclausenamidone and S- neoclausenamidone were higher than 99.9%, and the enantiomeric ratio (er) values of these isomers were 100:0. Enantioselectivity and resolution (α and Rs, respectively) levels with values ranging from 1.03 to 1.99 and from 1.54 to 17.51, respectively, were achieved. The limits of detection and quantitation were 3.6 to 12.0 and 12.0 to 40.0 ug/mL, respectively. In addition, the thermodynamics study showed that the result of the mechanism of chiral separation was enthalpically controlled at a temperature ranging from 288.15 to 308.15K. Furthermore, docking modeling showed that the hydrogen bonds and π-π interactions were the major forces for chiral separation. The present chiral HPLC method will be used for the enantiomeric resolution of the clausenamidone derivatives.

Chiral separation and modeling of quinolones on teicoplanin macrocyclic glycopeptide antibiotics CSP.

New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150×4.6mm, 5.0μm). Three mobile phases used were MeOH:ACN:Water:TEA (70:10:20:0.1%), (60:30:10:0.1%), and (50:30:20:0.1%). The flow rate of the mobile phases was 1.0mL/min with UV detection at different wavelengths. The values of retention, resolution, and separation factors ranged from 1.5 to 6.0, 1.80 to 2.25, and 2.86 to 6.0, respectively. The limit of detection and quantification ranged from 4.0 to 12ng and 40 to 52ng, respectively. The modeling studies indicated strong interactions of R-enantiomers with teicoplanin chiral selector than S-enantiomers. The supra molecular mechanism of the chiral recognition was established by modeling and chromatographic studies. It was observed that hydrogen bondings and π-π interactions are the major forces for chiral separation. The present chiral HPLC method may be used for enantiomeric resolution of quinolones in any matrices.

Development of high performance liquid chromatography method for miconazole analysis in powder sample

A simple high performance liquid chromatography (HPLC) method has been developed in this study for the analysis of miconazole, an antifungal drug, in powder sample. The optimized HPLC system using C8 column was achieved using mobile phase composition containing methanol:water (85:15, v/v), a flow rate of 0.8 mL/min, and UV detection at 220 nm. The calibration graph was linear in the range from 10 to 50 mg/L with r2 of 0.9983. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 2.24 mg/L and 7.47 mg/L, respectively. The present HPLC method is applicable for the determination of miconazole in the powder sample with a recovery of 101.28 % (RSD = 0.96%, n = 3). The developed HPLC method provides short analysis time, high reproducibility and high sensitivity.

Quantitative determination of regorafenib and its two major metabolites in human plasma with high-performance liquid chromatography and ultraviolet detection.

A simple, highly sensitive and specific high-performance liquid chromatography (HPLC) method was developed for the simultaneous quantitation of regorafenib, N-oxidemetabolite (M-2) and the desmethyl N-oxide metabolite (M-5) in human plasma. Regorafenib, M-2, M-5 and the internal standard sorafenib were separated using a mobile phase of 0.5% KH2 PO4 (pH 3.5)-acetonitrile (30:70, v/v), on a Capcell PAK MG II column at a flow rate of 0.5 mL/min and measurement at UV 260 nm. The lower limits of quantification for regorafenib, M-2 and M-5 were 10 ng/mL for each analyte. A procedure using solid-phase extraction required only a small amount of plasma (100 μL) for one analysis while providing high extraction recovery (>81% for all compounds) and good selectivity. Coefficients of variation for intra- and inter-day assays were <12.2% for regorafenib, <12.3% for M-2 and <15.1% for M-5. Accuracies for intra- and inter-day assays were <9.4% for regorafenib, <8.0% for M-2 and <12.8% for M-5 over a linear range from 10 to 10,000 ng/mL. This HPLC assay is suitable for clinical pharmacokinetic studies of regorafenib. The present HPLC method is currently in use for our observational studies of patients under treatment. Copyright © 2016 John Wiley & Sons, Ltd.

A high-performance liquid chromatography assay with a triazole-bonded column for evaluation of d-amino acid oxidase activity.

Elution profiles of kynurenic acid (KYNA) and 7-chlorokynurenic acid (Cl-KYNA) were examined by high-performance liquid chromatography (HPLC) using a triazole-bonded stationary phase column (Cosmosil® HILIC) under isocratic elution of a mobile phase consisting of CH3 CN-aqueous 10 mm ammonium formate between pH 3.0 and 6.0. The capacity factors of KYNA and Cl-KYNA varied with both the CH3 CN content and the pH of the mobile phase. The elution order of KYNA and Cl-KYNA was reversed between the CH3 CN- and H2 O-rich mobile phases, suggesting that hydrophilic interactions and anion-exchange interactions caused retention of KYNA and Cl-KYNA in the CH3 CN- and H2 O-rich mobile phases, respectively. The present HPLC method using a triazole-bonded column and fluorescence detection (excitation 250 nm, emission 398 nm) was applied to monitor in vitro production of KYNA from d-kynurenine (d-KYN) by d-amino acid oxidase (DAO) using Cl-KYNA as an internal standard. A single KYNA peak was clearly observed after enzymatic reaction of d-KYN with DAO. Production of KYNA from d-KYN was suppressed by the addition of commercial DAO inhibitors. The present HPLC method can be used to evaluate DAO activity and DAO inhibitory effects in candidate drugs for the treatment of schizophrenia.

Stereoselective analysis of flecainide enantiomers using reversed‐phase liquid chromatography for assessing CYP2D6 activity

Stereoselective analyses of flecainide enantiomers were performed using reversed-phase high-performance liquid chromatography (HPLC) equipped with a polysaccharide-based chiral column (Chiralpak AS-RH) and fluorescence detector. Excitation and emission wavelengths were set at 300 and 370 nm, respectively. Flecainide enantiomers in serum and urine were extracted using diethyl ether. The mobile phase solution, comprising 0.1 m potassium hexafluorophosphate and acetonitrile (65:35, v/v), was pumped at a flow rate of 0.5 mL/min. The recoveries of flecainide enantiomers were greater than 94%, with the coefficients of variation (CVs) <6%. The calibration curves of flecainide enantiomers in serum and urine were linear in the concentration range 5-500 ng/mL and 0.75-15 µg/mL (r > 0.999), respectively. CVs in intra-day and inter-day assays were 1.8-5.8 and 3.4-7.5%, respectively. In a pharmacokinetic study, the ratios of (S)- to (R)-flecainide (S/R ratio) in the area under the curve and the amount of flecainide enantiomers excreted in urine were lower in a subject carrying CYP2D6*10/*10 than in subjects carrying CYP2D6*1/*2. The S/R ratio of trough serum flecainide concentration ranged from 0.79 to 1.16 in patients receiving oral flecainide. The present HPLC method can be used to assess hepatic flecainide metabolism in a pharmacokinetic study and therapeutic drug monitoring.

Separation and quantitative determination of 6α-hydroxycortisol and 6β-hydroxycortisol in human urine by high-performance liquid chromatography with ultraviolet absorption detection

The present study developed an high-performance liquid chromatography (HPLC) method for the simultaneous determination of urinary metabolites of endogenous cortisol, 6α-hydroxycortisol (6α-OHF) and 6β-hydroxycortisol (6β-OHF), in human urine, using 6α-hydroxycorticosterone as internal standard. 6α-OHF and 6β-OHF were extracted from urine with ethyl acetate by using a Sep-Pak C(18) plus cartridge. Separation of the stereoisomers was achieved on a reversed-phase hybrid column by a gradient elution of (A) 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH (pH 3.77) and (B) 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH/acetonitrile (2:3, v/v). 6α-OHF and 6β-OHF were well separated on an XTerra MS C(18) 5 μm column using two types of stepwise gradient elution program (programs 2 and 3). Resolutions of 6α-OHF and 6β-OHF were Rs = 4.41 for program 2 and Rs = 4.60 for program 3. The analysis was performed within 23~26 min, monitored by UV absorbance at 239 nm. The lower limits of detection of 6α-OHF and 6β-OHF were 0.80 ng per injection (s/n = ca. 8), and the lower limits of quantification were 5.02 ng/ml for 6α-OHF and 41.08 ng/ml for 6β-OHF, respectively. The within-day reproducibilities in the amounts of 6α-OHF and 6β-OHF determined were in good agreement with the actual amounts added, the relative errors being -5.37% and -3.73% (gradient 2) and -5.69% and -3.96% (gradient 3) for both 6α-OHF and 6β-OHF, respectively. The inter-assay precisions (RSDs) for 6α-OHF and 6β-OHF were less than 1.99% (gradient 2) and 2.61% (gradient 3), respectively. The present HPLC method was applied to the measurement of 6α-OHF and 6β-OHF in urine to evaluate the time courses of 6α-hydroxylation and 6β-hydroxylation clearances of cortisol during 40 days for phenotyping CYP3A in a healthy subject.

Determination of debrisoquine and 4-hydroxydebrisoquine by high-performance liquid chromatography: application to the evaluation of CYP2D6 genotype and debrisoquine metabolic ratio relationship

The drug-metabolizing cytochrome P450 (CYP) enzyme CYP2D6 is involved in the metabolism of several clinically important drugs. So far more than 50 different CYP2D6 allelic variants have been described, and thus there is an increased need for routine high-performance liquid chromatography (HPLC) methods for the evaluation of the functional implication of CYP2D6 polymorphism. Debrisoquine is metabolized to 4-hydroxydebrisoquine by CYP2D6, and therefore it has been used widely to determine the hydroxylation capacity of the enzyme. The aim of the present study was to develop a simple, accurate HPLC method with ultraviolet detection for the measurement of debrisoquine and 4-hydroxydebrisoquine in urine for evaluation of the relationship between CYP2D6 enzyme activity and genotypes. For the HPLC determination, a C18 extraction column was used with a flow rate of 0.8 mL/min and detection at 210 nm. The compounds were eluted from the column in less than 10 min. Coefficients of variation at all concentrations were less than 4% for both compounds. The debrisoquine/4-hydroxydebrisoquine ratio (debrisoquine metabolic ratio) was determined in a panel of 16 Caucasian healthy volunteers with zero (poor metabolizers), one, two or more than two (ultrarapid metabolizers) CYP2D6 active genes. Significant correlation (p<0.05) between the number of CYP2D6 active genes and the hydroxylation capacity of the enzyme was found. The present HPLC method was simple, fast and accurate, and thus will be useful for the evaluation of CYP2D6 hydroxylation capacity in pharmacogenetic studies.

Simple method for the assay of clindamycin in human plasma by reversed-phase high-performance liquid chromatography with UV detector

A rapid and simple high-performance liquid chromatography (HPLC) method was developed and validated for the quantification of clindamycin in human plasma. After precipitation with 50% trichloroacetic acid (TCA) containing the internal standard, propranolol, the analysis of the clindamycin level in the plasma samples was carried out using a reverse-phase cyano (CN) column with ultraviolet detection (204 nm). The chromatographic separation was accomplished with an isocratic mobile phase consisting of acetonitrile-distilled water-7.6 mm tetramethylammonium chloride (TMA) (60:40:0.075, v/v/v), adjusted to pH 3.2. The proposed method was specific and sensitive with a lower limit of quantitation (LLOQ) of 0.2 microg/mL. This HPLC method was validated by examining the precision and accuracy for inter- and intraday analysis in the concentration range 0.2-20.0 microg/mL. The relative standard deviations (RSD) in the inter- and intraday validation were 6.1-14.9 and 6.0-16.1%, respectively. In the stability test, clindamycin was found to be stable in human plasma during the storage and assay procedure. The present HPLC method was applied to the analysis of samples taken up to 12 h after a single oral administration of clindamycin in healthy volunteers.

Analysis of Membrane Phospholipid Peroxidation by Isocratic High-Performance Liquid Chromatography with Ultraviolet Detection

A new high-performance liquid chromatography (HPLC) for separation of phospholipid classes with ultraviolet (UV) detection at 210 nm was applied to study of peroxidation of the human erythrocyte membranes induced by soybean lipoxygenase. Phospholipid hydroperoxide production of each phospholipid was monitored at the same time by UV at 234 nm. Each phospholipid class was collected directly from the HPLC of phospholipids and was subjected to fatty acid analysis. All phospholipid classes except sphingomyelin were significantly decreased by lipoxygenase. Production of each phospholipid hydroperoxide was according to the decrease of its corresponding phospholipid class. Polyunsaturated fatty acids of each phospholipid were preferentially decreased with lipoxygenase, and degrees of the changes of the phospholipid classes corresponded to the amount of polyunsaturated fatty acids of each phospholipid. α-Tocopherol suppressed the decrease of the membrane phospholipids by peroxidation and suppressed also the production of malondialdehyde. However, production of phospholipid hydroperoxides appeared to be not suppressed by α-tocopherol. The present HPLC method proved to be sensitive to peroxidation of phospholipids and could detect the changes of each phospholipid class including phosphatidylserine and phosphatidylinositol at a single chromatographic elution. Production of hydroperoxide of each phospholipid could be detected simultaneously.

Separation of major mononitro-aromatic compounds by reversed-phase high-performance liquid chromatography.

A simple analytical method was developed to determine p-nitrochlorobenzene (p-NCB) in working environmental air by reversed-phase high-performance liquid chromatography (HPLC). Nitrobenzene, nitrotoluene isomers, and NCB isomers were separated and p-NCB was determined by reversed-phase HPLC as follows: column; Hitachi gel #3056 (4.0 mm I.D. x 150 mm), mobile phase; 2-propanol: water (40:60, v/ v) with a flow rate of 0.8 ml/min, column temperature; 50 degrees C, detector; UV detector at 270 nm. Nitrobenzene, o-, p-nitrotoluene, and o-, m-NCB were separated from p-NCB, but m-nitrotoluene could not be completely separated from p-NCB. The limit of detection (signal-to-noise ratio of 3:1) of p-NCB was 0.3 ng. Repeatability of the HPLC method was excellent. The HPLC method enabled to determine one-tenth of the administrative level (1 mg/m3) of p-NCB, since the lower limit of determination was 0.05 mg/m3. Therefore, the present HPLC method proved to be applicable to the determination of p-NCB in working environmental air.

Quantitation of urinary chlorobenzene metabolites by HPLC: concentrations of 4-chlorocatechol and chlorophenols in urine and of chlorobenzene in biological specimens of subjects exposed to chlorobenzene

A simple method for the determination of 4-chlorocatechol (ClCh, 4-chloro-1,2-benzenediol) and chlorophenols (ClPh), metabolites of monochlorobenzene (ClBz), in urine by high performance liquid chromatography (HPLC) is described. Enzymatic hydrolysates of urine were applied to a stainless-steel column packed with octadecyl-silanized silica gel, and a mixed solution of 20 mM potassium phosphate monobasic: acetonitryl (75:25, v/v) was used as a mobile phase. The procedures for ether extraction and evaporation of extract could be omitted. The accuracy and precision of the present HPLC method were satisfactory. The excretion kinetics of ClCh and p-ClPh were investigated over 35 h after cessation of ClBz inhalation. Proportional relationships between concentrations of ClBz in air and of its metabolites in urine were observed. The slopes of regression lines predicting the levels of ClCh, p-ClPh and total ClPh in urine taken during the last 2 h of exposure to ClBz in air were 6.56, 1.13 and 2.83 mg/g creatinine for 1 ppm ClBz, respectively. ClBz in the blood and the end exhaled air of subjects at the end of exposure were identified by gas chromatography (GC) and mass spectrometry. A proportional relationship was observed between the concentration of ClBz in air and that in blood. The validity of the threshold limit value (TLV) for ClBz as evaluated from the subjective and objective symptoms is discussed.

Fluorometric determination of prostaglandins and thromboxane in plasma by high-performance liquid chromatography.

The high-performance liquid chromatography (HPLC) method for detecting prostaglandins (PGs) and thromboxane (TX) which was reported previously was found to have a serious problem in the detection of PGs and TX. In the present study, we tried to solve this problem by developing a sensitive HPLC method for determining PGs and TX in human plasma. An analytical wavelength (412nm when excited at 350nm) which was not interfered with by the Raman spectrum was found to be suitable for the detection of PGs- and TX-ADAM (9-anthryldiazomethane) derivatives. Moreover, partial purification of 9-anthyryldiazomethane (ADAM) derivatives by using a GEL PACK-A110 column enabled us to remove interfering substances from the chromatogram. The levels of 6-Keto-PGF1, PGE2 & D2, PGF2 and TXB2 in plasma were detected simultaneously using our method. The present HPLC method is useful for determining the PGs and TX levels in biological samples.

Quantitative Determination of Mono-, Di-, and Triacylglycerols of Saturated Fatty Acids for Production Control by High Performance Liquid Chromatography using Gel Permeation Column

High performance liquid chromatography (HPLC) using gel permeation column was developed for the quantitative determination of saturated acylglycerols. It was possible to separate acylglycerols into their respective homologs within 20 min using Shim-pack HSG-15 H column (30 cm × 7.9 mm i.d.) under the following conditions : mobile phase, tetrahydrofuran; flow rate, 0.5mL/min; detector, refractive index detector. Mono-, di- and triacylglycerols in saturated acylglycerols were determined simultaneously using hexastearoyldipentaerythritol (HSDP) as the internal standard. This method had excellent reproducibility and was highly accurate. The determination of free glycerol and a relative response factor (RRF) method are also described. The present HPLC method was found quite very useful for the quality and process control of acylglycerol emulsifiers.

HPLC Determination of Betamethasone-17-valerate in Commercial Ointment and Admixtures

High performance liquid chromatography (HPLC) was used in determination of betamethasone-17-valerate (BM-V) incommercial ointment. The conditions of HPLC were as follows-model: Shimadzu LC-4A; detector: SPD-2SA; wavelength: 239nm; column: Zorbax ODS (4.6×250mm); short guard-column: Zorbax ODS (4.0×50mm); mobile phase: MeOH: H2O= 75: 25 (v/v); flow rate: 1ml/ min; pressure: 100kg/cm2 (at 40°C). BM-V in commercial ointment and other ointment or cream admixture was also measured by the present HPLC method. BM-V ointment or admixture was dissolved or suspended into cyclohexane, and then MeOH: H2O (9: 1 or 8: 2) was used to extract BM-V from cyclohexane. Naphthalene was used as an internal standard material. 10μl of extract solution was directly injected into HPLC column. The amount of BM-V was determined by comparing the peak height of BM-V to that of naphthalene on the chromatogram.The results showed the possibility that compatibility of BM-V ointment admixed with other ointment or cream can be studied with the present method.