The article discusses the use of aqueous-ethanol mobile phases for the chromatography of azilsartan medoxomil, with the goal of developing an environmentally friendly method for determining the active ingredient in finished pharmaceutical forms. The research was conducted using the Shimadzu Nexera LC-30 liquid chromatograph with a diode-array detector and a Zorbax SB-Phenyl 250×4.6 (5 mm) chromatographic column. The impact of pH on the UV spectrum was tested, and it was found that, regardless of pH, the optimal wavelength for spectrophotometric detection is about 250 nm. This indicates that the same wavelength can be used for accurate detection of azilsartan medoxomil, even with pH variations in the solution. The effect of pH on the mobile phase in the reversed-phase chromatographic mode was also studied. The retention factors were found to decrease within the selected pH values of 2,0, 4,0, and 7,0, with values of 13,0, 11,9, and 1,7, respectively. This suggests a change in the chemical properties of the molecule depending on the pH, particularly the dissociation of the molecule as pH increases. Additionally, the effect of varying the organic component content in the mobile phase was determined. When the ethanol content in the solution was varied from 50% to 80% by volume, the retention factor decreased from 11,9 to 0,8. Increasing the organic component content reduces the retention time of the compound on the column, which allows for the regulation of the retention time. It was also established that the azilsartan medoxomil molecule undergoes rapid hydrolysis, converting into azilsartan, which could affect the accuracy of measurements if the substance is not stable during the analysis. The stability of azilsartan medoxomil in environmentally friendly solvents was tested at room temperature and during refrigerated storage. The results showed that azilsartan medoxomil has sufficient stability for analysis using freshly prepared solutions when solvents like dimethyl sulfoxide or 96% ethanol are used. It was also found that analytical solutions prepared with 96% ethanol are more stable when stored at 5°C. Moreover, stability was further enhanced when absolute ethanol was used as the solvent, which is a crucial factor for improving the accuracy of the analysis. The obtained results suggest the possibility of developing an environmentally friendly chromatographic method using ethanol as a component of the mobile phase and as a solvent for sample preparation. This opens the potential for creating safer and more eco-friendly methods in pharmaceutical analysis.

As of 2023, more than 500 pesticides have been registered for use in agriculture in Ukraine, which include active substances (A.S.) from the triazole class. They make up almost half of the total number of fungicides and more than a third of the total number of seed treatments. Among them, the share of mixed preparations is constantly growing: among fungicidal preparations, they already account for more than half, and among seed treatments, for more than two thirds. To determine triazole residues for pre-registration trials, many methods based on gas-liquid chromatography and high-performance liquid chromatography have been developed. For routine analysis, multi-residue "MRM-methods" are used, in particular with sample preparation according to the QuEChERS methodology. In recent years, such methods have also been used in pre-registration trials of pesticides, especially mixed ones. The purpose of this study was to develop and standardize methodological approaches for the determination of residual quantities of triazole-based fungicides to substantiate and control their safe use in agriculture. Gas-liquid capillary chromatography with electron capture and thermionic detectors; gas-liquid chromatography-mass spectrometry; high-performance liquid chromatography with a diode array detector was used in this study. A set of methods for the determination of fungicides, in particular mixed ones, which include active substances from among triazoles and other classes of chemical compounds, has been developed. The methods are based on a combination of various chromatographic methods (gas-liquid and high-performance liquid chromatography, chromatography-mass spectrometry) using the modern QuEChERS sample preparation methodology. The application of the proposed methodological developments allowed to conduct pre-registration trials of new fungicide preparations, in particular mixed ones, and to substantiate the conditions of their safe use in agriculture.

In the pharmaceutical industry, cleaning of technological equipment and laboratory glassware plays a crucial role in ensuring the quality and safety of pharmaceutical products. In this study, we investigated the possibilities for reducing the limit of quantification using HPLC-UV for determining small amounts of substances in washings from technological equipment. In the research Knauer Azura chromatograph was used, equipped with the Azura DAD 6.1 diode-array detector with a 50mm fiber-optic flowcell. The chromatographic columns used was the Discovery HS F5 250×4,6 (5 µm) and Discovery HS C18 250×4,6 (5 mm). It was shown that the use of aqueous-ethanol mixtures in combination with pentafluorophenyl stationary phase (Discovery HS F5) achieves better retention of the model substance – caffeine, compared to octadecylsilane (Discovery HS C18). Using Discovery HS F5 and a mobile phase containing 40% ethanol in water, the retention factor was 0,7, while using Discovery HS C18 under the same conditions, the retention factor was 0,2. The advantages of using ethanol compared to acetonitrile were also demonstrated, as using 40% acetonitrile in the mobile phase resulted in a lower retention factor of 0.4. The effect of increasing the injection volume on the chromatographic peak characteristics was investigated, and it was shown that when a sample solvent with a lower eluting strength than the mobile phase is used, the injection volume can be increased up to 250 ml, which leads to a lower limit of quantification. By increasing the injection volume, a low limit of quantification is achieved, which is commensurate with the limit of quantification observed for the HPLC-MS method. Thus, when injecting 250 ml of the test solution into the system, it was possible to achieve a limit of quantification of 0,27 ng/ml. The results of the study expand the scope of the HPLC-UV method as a potential alternative to the high-cost HPLC-MS method for analyzing residue quantities of pharmaceuticals during the cleaning validation of technological equipment or laboratory glassware.

Aliphatic and aromatic aldehydes and ketones are used in organic synthesis, in the production of medicines, pesticides, short-chain ketones are used as organic solvents. Carbonyl compound impurities can be present in polymeric materials, environmental objects, pharmaceuticals, food products, and wood products, and aldehydes and ketones can also be present in biological fluids. Carbonyl compounds have harmful effects on the environment and living organisms; some of them, namely, formaldehyde and acrolein, are carcinogens. Therefore, an important task is the development and improvement of methods for sample preparation and quantitative determination of carbonyls. A method of solid-phase extraction (SPE) of aromatic aldehydes, in combination with HPLC/UV determination, has been developed for the analysis of soft drinks. A SPE cartridge was filled with C18 silica gel impregnated with 2,4-dinitrophenylhydrazine (DNPH). The developed method includes the steps of sorption, derivatization, and elution of carbonyl compounds, which were carried out sequentially in dynamic mode. The following parameters were optimized: type of sorbent, mineral acid and its concentration, concentration of DNPH on the sorbent, and volume of aqueous sample. When an aqueous solution of aldehydes was passed through the SPE cartridge, aromatic aldehydes were sorbed on the sorbent and converted into DNPH-hydrazones, then the derivatives were eluted with acetonitrile and determined by HPLC/UV. The limit of detection using the 3s-criterion was 1-2 mg/L for 2-furaldehyde and benzaldehyde. 2-furaldehyde was determined in ground and instant coffee. The method of standard additions was applied to eliminate the matrix effects. The relative standard deviation did not exceed 2,5%. The advantages of the sample preparation method of aromatic aldehydes are rapidity, simplicity, small amount of initial sample, economy of toxic organic solvents, and sufficiently high selectivity of determination.

Standardization of herbal medicines is a crucial aspect of the pharmaceutical industry, ensuring quality control, efficacy, and safety of plant-based medicinal products. One of the challenges in the analysis of herbal medicines is the complexity of determining biologically active compounds in multicomponent plant formulations. This study presents an optimized spectrophotometric method for the quantitative determination of valepotriates, which can be used for the standardization of herbal medicines intended for the prevention and treatment of cardiovascular diseases. The method is based on the ability of valepotriates to degrade in an acidic medium, forming colored compounds with a maximum absorption at 595 nm. To ensure reproducibility and accuracy, we investigated the effect of various organic solvents on the extraction efficiency of valepotriates. The solvents studied included chloroform, n-hexane, methylene chloride, and petroleum ether. It was found that the use of petroleum ether minimizes the interference of accompanying components and provides the best analytical characteristics for the method. The validation of the method confirmed its specificity, linearity (r = 0.9998), accuracy, and precision (ΔZ = 1.9%). The average content of valepotriates in the samples was determined to be 15.34 ± 0.34%. To verify the effectiveness of the method, a comparative analysis was conducted using high-performance liquid chromatography (HPLC). The results demonstrated a strong correlation between the methods, indicating no statistically significant differences (15.46 ± 0.34%, p > 0.05). Compared to HPLC, the spectrophotometric method is simpler, does not require expensive equipment, and can be implemented in pharmaceutical laboratories for routine quality control of herbal medicines. The high sensitivity and selectivity of the method allow for the analysis of complex multicomponent mixtures without the need for preliminary separation of components. The proposed approach is promising for ensuring the quality control of plant-based medicinal products and contributes to improving their efficacy and safety.

The purpose of this work is to analyze the chronology and state of development of chromatographic methods at the Zaporizhzhia State Medical University (ZSMU). A historical overview of the use of chromatographic methods at ZSMU is provided. First of all, emphasis is placed on the introduction of high-performance liquid chromatography and gas-liquid chromatography. The main scientific laboratories and groups that worked and are working at the Zaporizhzhia State Medical University in the field of instrumental chromatography are shown. There were groups at the Department of Biological Chemistry, the Department of Faculty Pediatrics, the Department of Physical and Colloidal Chemistry. Currently, the Department of Physical Colloid Chemistry is actively working on a new laboratory of liquid chromato-mass spectrometry of the Department of Experimental Pharmaceutical Research of the training medical-laboratory center. The laboratory performs research for many departments of ZSMU, including the Faculty of Pharmacy, the Faculty of Postgraduate Education, the Faculty of Medicine. The laboratory develops, validates and uses methods to establish the purity and confirm the molecular weight and structure of new biologically active substances synthesized to search for new drugs, research of impurities in drug substances, determination of biologically active substances in extracts of medicinal plant raw materials, determination of residual amounts drugs in poultry meat and eggs, and other livestock and poultry products, determination of concentrations of disease markers, determination of distribution, metabolism and excretion of drugs.

The effect of carbonization temperature on canarium schweinfhurthii seed shell was investigated. Atili seed shell particles was carbonized at different temperatures of 600, 800, 1000 and 1150°C under inert condition for 60 mins each to obtain char products. The effect of temperature on the properties of char was investigated in detail, using several characterization techniques including, mass yield, elemental analysis, and electrical property measurements while structural transformations were monitored using X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) techniques. The char yield decreased from 30.50 % to 26.55 % as the temperature increases from 600°C to 1150°C. The fixed carbon (82.3 to 92.66 %) and ash content (1.35 to 1.72 %) increase as temperature increase while the volatile matter (12.61 to 4.18 %) and moisture content (3.81 to 1.44 %) decreases. Ultimate analysis showed elemental carbon to increase from 85.96 % to 95.79 %. The electrical conductivity of obtained char improved significantly (1.99 x 10-9 to 7.24 x 10-2 S/cm) as well as the structural, morphology and near graphitization of char. Statistical analysis of the FTIR and XRD data via the principal component analysis showed similarity trend on the effect of temperature on the carbonization products. The improved electrical property, pore development in char morphology as well as the development of near graphitization features suggest possible use as electrode materials.

The review of the development of micellar high-performance liquid chromatography and micellar thin-layer chromatography is presented. The results of the research of the theoretical foundation and the organized solution usage as mobile phases for the analysis of plant and animal biological active substances, medicinal substances and drugs are demonstrated. The investigations had been carried out on the Chemical Metrology Department V.N. Karazin Kharkiv National University and in the State Enterprise “Ukrainian Scientific Pharmacopoeial Center for Quality of Medicines”.