Chromatographic behaviour of selected steroids and their inclusion complexes with beta-cyclodextrin on octadecylsilica stationary phases with different carbon loads

Conductometric Studies of Formation the Inclusion Complexes of Phenolic Acids with β-Cyclodextrin and 2-HP-β-Cyclodextrin in Aqueous Solutions

An attempt was made to evaluate the possibility of creating and assessing the stability of inclusion complexes of selected phenolic acids [trans-4-hydroxycinnamic acid (trans-p-coumaric acid), trans-3,4-dihydroxycinnamic acid (trans-caffeic acid), trans-4-hydroxy-3-methoxycinnamic acid, (trans-ferulic acid) and trans-3-phenylacrylic acid (trans-cinnamic acid)] with β-cyclodextrin and 2-HP-β-cyclodextrin in aqueous solutions in a wide temperature range 283.15 K-313.15 K. On the basis of the values of the limiting molar conductivity (Λ_CDNaDod), calculated from the experimental data, the values of the formation constants and the thermodynamic functions of formation (standard enthalpy, entropy, and Gibs standard enthalpy) of the studied complexes were determined. It has been found that the stability of the studied complexes increases with lowering of the molar mass of cyclodextrin and lowering of the temperature.

Analysis of Selected Endocrine Disrupters Fraction Including Bisphenols Extracted from Daily Products, Food Packaging and Treated Wastewater Using Optimized Solid-Phase Extraction and Temperature-Dependent Inclusion Chromatography

The aim of this research is to demonstrate the concept and ability for the fast and preliminary screening of complex food and environmental samples for the presence of endocrine disrupters fractions, consisting of low-molecular mass micropollutants, particularly various bisphenols (A, B, C, E, F, S, Z, AF, AP, BP and FL). The developed analytical protocol for this research requires two main steps: (i) optimized solid phase extraction (SPE) for selective isolation, purification and pre-concentration of target fraction, and (ii) selective temperature-dependent inclusion chromatography for samples analysis via a HPLC-UV-VisDAD system using isocratic elution and internal standard quantification approach. The chromatographic experiment revealed that both β-CD and its hydroxypropyl derivative strongly interact with selected bisphenols. This is in contrast to the steroids and PAHs molecules investigated previously, where a strong interaction with β-cyclodextrin was observed. Integrated areas derived from acquired chromatographic profiles for each individual sample were used as the simple classification variable enabling samples comparison. We demonstrated that the proposed analytical protocol allows for fast estimation of EDC fractions in various daily use products, food and environmental samples. The materials of interest were selected due to the presence in surface water ecosystems of their residues, and finally, in raw wastewater including rice bags, plastic bags, cloths, sanitary towels, fish baits and various plastic foils from food products. Treated sewage water released directly to the environment from a municipal treatment plant (Jamno, Koszalin) was also investigated. It has been demonstrated that a whole range of low-molecular mass compounds, which may be detected using UV-Vis detector, can easily be emitted from various in daily use products. The presence of micropollutants in treated wastewater, water ecosystems and plastic waste utilization via technological wastewater treatment processes must be addressed, especially in terms of microplastic-based pollutants acting as endocrine disrupters. It is hoped that the proposed simple analytical protocol will be useful for fast sample classification or selection prior to advanced targeted analysis involving the more accurate quantification of specific analytes using e.g., mass spectrometry detectors.

Interaction of native alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin and their hydroxypropyl derivatives with selected organic low molecular mass compounds at elevated and subambient temperature under RP-HPLC conditions

The main focus of this study was to explore the capability of native alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin and their hydroxypropyl derivatives for host-guest interaction with 7,8-dimethoxyflavone, selected steroids (estetrol, estriol, estradiol, estrone, testosterone, cortisone, hydrocortisone, progesterone and 17alpha-hydroxyprogesterone) and polycyclic aromatic hydrocarbons (toluene, naphthalene, 1,8-dimethylnaphthalene, 1-acenaphthenol, acenaphthylene and acenaphthene) under reversed-phase liquid-chromatography conditions. The study revealed that native cyclodextrins interact more efficiently with the analytes investigated than do their hydroxypropyl counterparts. In the low-temperature region, enormously high ratios were observed for polycyclic aromatic hydrocarbons, particularly 1,8-dimethylnaphthalene, acenaphthene and acenaphthylene chromatographed on a beta-cyclodextrin-modified mobile phase. In such a case, the retention times of the polycyclic aromatic hydrocarbons were strongly reduced (e.g. from 127 to 1.2 min for 1,8-dimethylnaphthalene) and were close to the hold-up time of the high-performance liquid chromatography (HPLC) system (0.7 min). Moreover, chiral separation of 1-acenaphthenol optical isomers was observed and the elution order of the enantiomers was determined. Within the steroids group, strong interaction was observed for estradiol and testosterone. The results of cluster analysis indicate that beta-cyclodextrin as well as gamma-cyclodextrin and its hydroxypropyl derivative can be most effective mobile-phase additives under reversed-phase HPLC conditions for 3D-shape-recognition-driven separation, performed at subambient and elevated temperatures, respectively.

Characterization of human fetal cord blood steroid profiles in relation to fetal sex and mode of delivery using temperature-dependent inclusion chromatography and principal component analysis (PCA)

In the present work, human male and female fetal cord blood samples were purified, selectively extracted and separated to examine a fraction of steroids ranging from polar estetrol to relatively non-polar progesterone using solid phase extraction based on C-18 tubes and beta-cyclodextrin driven temperature dependent inclusion chromatography. Resulting UV diode array chromatographic patterns revealed the presence of 27 peaks. Chromatographic patterns of UV detected steroids were analyzed using principal components analysis which revealed differences between male/female and labour/not-in-labour clusters. Quantitative analysis of nine identified steroids including: estetrol, 17beta-estradiol, estrone, estriol, cortisol, cortisone, progesterone, 20 alpha-hydroxyprogesterone and 17 alpha-hydroxyprogesterone were not significantly different between males and females. Significant differences between male and female fetuses were related to as yet unidentified compounds. Four peaks were significantly different with labour which corresponded with cortisol, cortisone and two unidentified compounds. This protocol may distinguish significant differences between clinical groups that are not readily identifiable using univariate measurements of single steroids or different low molecular mass biomarkers. Moreover, we have provided new evidence that despite the absence of testosterone there are number of steroids and low molecular mass compounds that differ between male and female fetuses.

Use of β-cyclodextrin bonded phase with s-triazine moiety in the spacer for separation of aromatic carboxylic acid isomers by high-performance liquid chromatography

The separation and retention behavior of five aromatic carboxylic acid isomers was investigated by means of high-performance liquid chromatography (HPLC) using a beta-cyclodextrin bonded phase with s-triazine ring in the spacer. The influence of mobile phase pH on the retention was examined. The presence of s-triazine moiety in the spacer enhances greatly the selectivity of the isomers of aromatic carboxylic acids. Baseline separations of the five aromatic carboxylic acid isomers were achieved. In particular, the isomers of toluic, aminobenzoic, nitrobenzoic and hydroxybenzoic acid were successfully and effectively separated. The chromatographic results indicate that, in addition to inclusion complexation, pi-pi interaction and hydrogen bonding interaction between the bonded phase and analytes play significant roles in the retention of these acid isomers. Different elution orders were observed for these acidic solutes with different substituents. Possible retention mechanisms are discussed.

Evaluation of Methanol-Water and Acetonitrile-Water Binary Mixtures as Eluents for Temperature-dependent Inclusion Chromatography

In the present study the solubility of beta-cyclodextrin and 2-hydroxypropyl-beta-cyclodextrin at sub-zero and elevated temperatures (-10 and +30 degrees C) for a given composition of methanol/water and acetonitrile/water binary mixtures (Xs = 0.16) was studied. Moreover, the freezing temperature profiles of acetonitrile-based chromatographic mobile phases were measured, and the obtained results were compared with data available in the literature. Furthermore, the effect of the macrocycles concentration on the liquid-phase freezing points was determined. The low solubility of native beta-cyclodextrin in a methanol/water mixture at sub-zero temperature as well as the non-linear behavior of acetonitrile/water mixtures that were observed concerning the freezing point profile are discussed from a practical point of view.

Determination of steroids in human plasma using temperature-dependent inclusion chromatography for metabolomic investigations

Clinical and metabolomic investigations of complex human fluids require cost-effective methodologies that can rapidly assess the steroid hormone milieu of individual samples. The efficiency of quantification of many steroids is limited using immunoassays as these methods can only measure a single component of biological samples and are dependent upon the specificity of the antiserum used in the protocol. In this study, we optimised the solid-phase extraction protocol for the extraction of a range of steroids of varied polarity from estetrol to progesterone from human plasma. The final SPE procedure for efficient extraction of steroids was a washing mixture of 5 ml of 30% methanol and an elution solvent of 2 ml of 100% methanol using 0.5 g C-18 cartridges. This protocol resulted in a high recovery rate, ranging from 85.2 to 99.9% for both the internal standard (7,8-dimethoxyflavone) and steroids of interest. We also improved the separation methodology of our previous work using temperature dependent inclusion chromatography with a mobile phase composition of 35% acetonitrile and 12 mM of beta-cyclodextrin at 29 degrees C. Under these conditions most of the fluid components including estetrol were detected in the first 10 min with progesterone appearing at 43 min. This method is simplistic, inexpensive and reproducible with the capabilities of accurate quantification of steroids. Therefore it could have numerous clinical and metabolomic applications.

Biotechnological applications of cyclodextrins

Cyclodextrins (CDs) are a family of cyclic oligosaccharides that are composed of alpha-1,4-linked glucopyranose subunits. Cyclodextrins are produced from starch by enzymatic degradation. These macrocyclic carbohydrates with apolar internal cavities can form complexes with and solubilize many normally water-insoluble compounds. This review describes recent applications of CDs in pharmaceuticals with a major emphasis on drug delivery systems. The utility of these water-soluble cyclic glucans in a variety of foods, flavors cosmetics, packaging and textiles is elaborated. The role of these compounds in biocatalysis is also discussed. Cyclodextrins are used in separation science because they have been shown to discriminate between positional isomers, functional groups, homologues and enantiomers. This property makes them a useful agent for a wide variety of separations.

Recent Advances in the Analysis of Steroid Hormones and Related Drugs

The development during the last 15 years and the state-of-the-art in the analysis of bulk steroid hormone drugs and hormone-like structures and pharmaceutical formulations made thereof are summarized. Other steroids (sterols, bile acids, cardiac glycosides, vitamins D) as well as biological-clinical aspects and pharmacokinetic and metabolic studies are excluded from this review. The state-of-the-art is summarized based on comparisons of monographs in the latest editions of the European Pharmacopoeia, United States Pharmacopoeia and the Japanese Pharmacopoeia. This is followed by sections dealing with new developments in the methodology for the fields of spectroscopic and spectrophotometric, chromatographic, electrophoretic and hyphenated techniques as well electroanalytical methods. The review is terminated by two problem-oriented sections: examples on impurity and degradation profiling as well as enantiomeric analysis.