Separation of ketoconazole enantiomers by chiral subcritical-fluid chromatography

A rapid method for the simultaneous stereoselective determination of the triazole fungicides in tobacco by supercritical fluid chromatography-tandem mass spectrometry combined with pass-through cleanup

This work presents a simple, rapid and green chiral analysis method for five triazole fungicides (penconazole, tebuconazole, triadimefon, myclobutanil, and triadimenol) in tobacco, by which the samples were cleaned up by the novel pass-through solid phase extraction and subsequently the stereoisomers were separated and determined by the supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS). Optimized separation of the stereoisomers was achieved on an ACQUITY UPC2 Trefoil AMY 1 column within 6 min. Under fortified concentration levels of 0.1, 0.5 and 2.0 mg/kg, the mean recoveries were 82.8-106.6%, the intra-day relative standard deviations (RSDs) were 1.1-6.6%, and the inter-day RSDs were 2.5-5.6%. The correlation coefficient was greater than 0.9926 for all studied analytes within the range of 10-500 ng/mL. The limits of detection (LODs) for all stereoisomers ranged from 0.26 μg/kg to 3.24 μg/kg. The established method was subsequently successfully applied to analyze authentic samples, confirming that this method is a novel, rapid and environmentally friendly method for the stereoselective separation of triazole fungicides in tobacco.

Enantioseparation of ketoconazole and miconazole by capillary electrophoresis and a study on their inclusion interactions with β-cyclodextrin and derivatives

A chiral separation method coupled with capillary electrophoresis (CE) analysis for ketoconazole and miconazole enantiomers using chiral selectors such as β-cyclodextrin (β-CD) and hydroxypropyl-β-CD (HP-β-CD) was developed in this study, which included the optimisation, validation and application of the method on the antifungal cream samples. The formation of inclusion complex between the hosts (β-CD and HP-β-CD) and guests (ketoconazole and miconazole) were compared and analysed using ultraviolet-visible spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy and molecular docking methods. Results from the study showed that in a concentration that ranged between 0.25 and 50 mg L^-1 , the linear calibration curves of each enantiomer had a high coefficient of regression (R² > 0.999), low limit of detection (0.075 mg L^-1 ) and low limit of quantification (0.25 mg L^-1 ). The relative standard deviation (RSD) of the intraday and interday analyses ranged from 0.79% to 8.01% and 3.30% to 11.43%, respectively, while the recoveries ranged from 82.0% to 105.7% (RSD < 7%, n = 3). The most probable structure of the inclusion complexes was proposed based on the findings from the molecular docking studies conducted using the PatchDock server.

Stability-Indicating Validated Novel RP-HPLC Method for Simultaneous Estimation of Methylparaben, Ketoconazole, and Mometasone Furoate in Topical Pharmaceutical Dosage Formulation

A simple, specific, precise, and accurate RP-HPLC method has been developed and validated for simultaneous estimation of Methylparaben (MP), Ketoconazole (KT), and Mometasone Furoate (MF) topical pharmaceutical dosage formulation. The separation was achieved by Waters X Terra C18 column using mobile phase consisting of buffer (triethyl amine in water, pH adjusted to 6.5 with glacial acetic acid)-acetonitrile (40 : 60, v/v) at a flow rate of 1.5 mL/min and detection at 250 nm. The method showed linearity with correlation coefficient <0.9999 over the range of 0.12–15.2 μg/mL, 0.67–149.4 μg/mL, and 0.42–7.6 μg/mL for MP, KT, and MF, respectively. The mean recoveries were found to be in the range of 99.9–101.1% for all the components. The method was validated as per the ICH guidelines for linearity, limit of detection, limit of quantification, accuracy, precision, robustness and solution stability. Stability indicating capability of the developed method was established by analyzing forced degradation of samples in which spectral purity of MP, KT, and MF along with separation of degradation products from analytes peak was achieved. The method can be successfully applied for routine analysis of quantitative determination of MP, KT, and MF in pharmaceutical dosage form.

Identification of major degradation products of ketoconazole

Analytical methods were developed for the identification of major degradation products of Ketoconazole, an antifungal agent. The stressed degradation of Ketoconazole drug substance was performed under acid, base, thermal, photo and oxidative stress conditions. The major degradation was observed under acid, base and oxidative stress conditions. The degradation study was performed on Inertsil ODS-3V, length 100 X diameter 4.6 mm, particle size 3 μm column using gradient method. These degradants were identified by LC-MS technique.

Enantiomeric separation of chiral sulfoxides by supercritical fluid chromatography

The application of supercritical fluid chromatography (SFC) to the enantiomeric separation of several chiral sulfoxides belonging to the family of the substituted benzimidazoles, including omeprazole, lansoprazole, pantoprazole, rabeprazole, oxfendazole and ricobendazole, is presented in this work. The column employed was Chiralpak AD and the effect of different chromatographic conditions was studied. The results obtained showed that all the compounds can be enantiomerically resolved using SFC, with resolutions higher than 2 and analysis times that in most cases were lower than 10 min. Alcohol type modifiers provided the best results, with ricobendazole, oxfendazole, and omeprazole showing the highest retentions and resolutions. Study of the temperature effect revealed that, in general, the isoelution temperature was above the temperatures assayed, except in the cases of omeprazole, lansoprazole, and oxfendazole with ethanol as modifier and pantoprazole with acetonitrile. Enthalpy-entropy compensation could also be demonstrated for the retention of the first and second eluted enantiomers as well as for the selectivity, with compensation temperatures of 25 degrees C, 45 degrees C, and 83 degrees C, respectively. Reversal of elution on change of the organic modifier was only observed for omeprazole using 2-propanol.

Enantiomeric separation of ketoconazole and terconazole antifungals by electrokinetic chromatography: Rapid quantitative analysis of ketoconazole in pharmaceutical formulations

EKC using a neutral CD as chiral selector was applied in this work to the development of a method enabling the enantiomeric separation of ketoconazole and terconazole antifungals. The influence of different experimental conditions such as temperature, CD concentration, pH, and nature and concentration of the buffer on the enantiomeric resolution of the compounds studied was investigated. The use of 10 mM heptakis-(2,3,6-tri-O-methyl)-beta-CD in a 100 mM phosphate buffer (pH 3.5) with a temperature of 15 degrees C allowed the separation of the enantiomers of ketoconazole and terconazole with high resolution (R(s) > 2.0). The rapid separation of ketoconazole enantiomers with an analysis time less than 3 min was carried out after fitting some experimental parameters. The developed method was applied to the determination of ketoconazole in different pharmaceutical formulations.

Chiral separation of omeprazole and several related benzimidazoles using supercritical fluid chromatography

A study of the enantiomeric separation of omeprazole and several related benzimidazoles, using supercritical fluid chromatography (SFC), on the amylose based column Chiralpak AD is presented in this work. The effect of the organic modifier as well as temperature on the retention and enantioresolution was investigated. Alcohol-type modifiers provided the best results, allowing the enantiomeric separation of all the compounds studied with resolutions that were in most cases higher than 2, and analysis times lower than 10 minutes. An investigation of the temperature effect revealed that the isoelution temperature was below the working temperature range in only two cases, and hence it was better to work at the highest temperature permitted.

Separation of triadimefon and triadimenol enantiomers and diastereoisomers by supercritical fluid chromatography

The enantiomeric separation of triadimenol and triadimefon on a Chiralpak AD column using supercritical fluid chromatography, was studied in this work. The effect of different modifiers (methanol, ethanol and 2-propanol) was tested, with methanol and ethanol providing the best results for the enantiomeric separation of the two compounds. The enantioseparation of a mixture of triadimenol and triadimefon (six stereoisomers) was achieved in only 15 min using a gradient of ethanol, 200 bar, 35 degrees C and a flow-rate of 2 ml/min. The separation of triadimenol diastereoisomers on different achiral columns (diol, silica and ODS) was also investigated. In this case, the type of organic modifier to be used depended on the stationary phase, the Spherex Diol being the column that gave the best separation. Using this column, resolutions higher than 3 were obtained in analysis times of 5 min with any of the modifiers checked.

Separation of antifungal chiral drugs by SFC and HPLC: a comparative study

The enantiomeric separation of several compounds, including an antifungal drug and several of its precursors, using HPLC and SFC is described in this work. The columns employed were based on polysaccharide derivatives and the results show that most of the separations obtained by SFC are better, in terms of high resolution and short analysis time, than those obtained by HPLC. Only one compound could not be resolved using SFC but, in this case, HPLC provided baseline resolution.

Separation of albendazole sulfoxide enantiomers by chiral supercritical-fluid chromatography

The enantioseparation of albendazole sulfoxide (ABZSO) by chiral supercritical-fluid chromatography (SFC) on two columns, based on the polysaccharide derivatives Chiralpak AD and Chiralcel OD, was studied. The effect of different modifiers, methanol, ethanol, 2-propanol, and acetonitrile, was examined. The results showed that ABZSO can be separated on both columns, using an alcohol-type modifier. Using the Chiralpak AD column, the best results were obtained with 2-propanol and, in the case of the Chiralcel OD, with methanol.

Applications of the Chiralpak AD and Chiralcel OD chiral columns in the enantiomeric separation of several dioxolane compounds by supercritical fluid chromatography

Two chiral columns based on polysaccharide derivatives (Chiralpak AD and Chiralcel OD) have been tested for the chiral separation of several dioxolane compounds, using supercritical fluid chromatography. The compounds studied included ketoconazole and some of its precursors. The effect of the different modifiers and the pressure, on the chromatographic parameters was also evaluated. In general, the alcohol modifiers provided better results than acetonitrile, and all the compounds could be separated with these two columns, but the selection of the column depends on the kind of compound.