Objectives. Currently, propofol emulsions are widely used in clinical practice due to their rapid action, low toxicity, and ease of administration, including control of anesthetic depth and rapid recovery of the patient following anesthesia. The market offers drugs from both foreign and domestic manufacturers containing imported pharmaceutical substances. The study set out to develop a technology for obtaining a fat emulsion of propofol for parenteral purposes using a high-pressure homogenizer based on pharmaceutical propofol obtained by alkylation and subsequent decarboxylation of 4-hydroxybenzoic acid, as well as to study the physicochemical properties of the obtained submicron emulsions.

Methods. A submicron propofol emulsion was prepared using a high-pressure homogenizer. pH was determined using a pH meter equipped with a combined glass electrode. Particle size and zeta potential of the submicron emulsion were determined on a laser particle analyzer using the dynamic and electrophoretic light-scattering methods, respectively. Quantitative propofol content in the resulting emulsion was determined using high-performance liquid chromatography.

Results. Optimal technological parameters of the high-pressure homogenization process were selected. The method of adding the oil phase directly into the high-pressure homogenizer is shown to entail lower time and energy costs as compared to the homogenization method involving a preliminary stage of obtaining a pre-emulsion. The physicochemical characteristics of the obtained submicron emulsions were subsequently determined to correspond to the characteristics required for the original drug Propofol-Lipuro®.

Conclusions. The proposed technology for obtaining a submicron propofol emulsion for parenteral use is based on dispersion of the aqueous and oil phases using a high-pressure homogenizer. As a result of the study, it was found that adding the oil phase directly into the high-pressure homogenizer at 20 MPa, including further dispersion at 60 MPa for 8 cycles, is optimal for obtaining a submicron propofol emulsion with the required characteristics.

Objectives. Exposure to ultraviolet (UV) radiation initiates a photo-oxidative degradation process in plastics that causes broken chemical bonds, weight loss, and weakened crosslinking, as well as the formation of free radicals and release of volatile substances. The work aims to study the influence of UV radiation on polystyrene films containing low concentrations of highly aromatic Schiff bases.

Methods. Utilizing the described casting technique, polystyrene films containing a small quantity of strong highly aromatic Schiff bases were produced. These films were then subjected to 300 h of UV irradiation. Following irradiation, analyses were conducted on the infrared spectra, weight loss, and surface morphology of the polystyrene.

Results. The surface of the sheets was initially smooth and free of wrinkles. However, following irradiation, remarkable morphological changes were observed as the surface became more uneven. Intentional perforations and imperfections introduced into the examined surfaces were used to indicate the degradation of the polymer matrices.

Conclusions. Highly aromatic Schiff bases act as photostabilizers to significantly reduce the extent of photodegradation in polystyrene films when compared to films with no additives.

Objectives. The work set out to summarize the results of the studies of aluminum oxynitrides (AlONs) doped with rare earth (REM) and transition metals (TM) and to highlight the main effects of REM and TM dopants on the formation, phase composition, and optical properties of the AlON.

Results. The presented analysis of the literature data includes the results of our own studies of the AlON doped with REM and TM ions. The influence of REM and TM additives on the formation of AlON and its phase com position, as well as optical properties, was considered.

Conclusions. It is clearly shown that the doping with REM and TM ions enhances the formation of pure AlON phase via high-temperature synthesis from oxide and nitride. The oxynitride matrix exhibits reducing properties with respect to both REM and TM. Doping with the REM ions leads to the emergence of luminescent properties in the visible range, while doping with TM ions affects the band gap in AlON as a semiconductor. The solubility limits of all metals in the AlON matrix do not exceed 1–2 at. % vs Al. Concentration quenching of luminescence is observed at REM contents from 0.1 to 0.5 at. %.

Objectives. This study aims to synthesize strontium hexaferrites having a high level of chromium substitution (SrFe_12−x Cr_x O₁₉, x = 0–6) and investigate their structural, morphological, and magnetic properties.

Methods. The synthesis was carried out using the solid-phase reaction method at a temperature of 1400°C. The impact of chromium substitution for iron on the phase, structure, morphology, and magnetic characteristics was studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and vibrating-sample magnetometry.

Results. XRD analysis confirmed the development of single-phase samples having a hexagonal space group P6₃/mmc. An increase in Cr concentration leads to a decrease in unit cell parameters, due to the smaller ionic radius of Cr³⁺. The surface morphology of the samples consists of bulk crystallites a few microns in length. Substitution with Cr results in decreased saturation and remanent magnetization.

Conclusions. Pure samples of Cr-substituted strontium hexaferrite were synthesized. The linear dependence of the investigated structural parameters on the Cr concentration confirms the Cr substitution into the hexaferrite solid solution by Vegard’s law. In addition to structural parameters, magnetic characteristics were obtained for hexaferrite solid solutions. Saturation and remanent magnetization dependencies were shown to significantly decrease with Cr concentration, while coercive force varies in a complex dependence on Cr concentration. The sample with x = 1 has the highest product of coercive force and saturation magnetization, indicating its suitability for permanent magnet application.

Objectives. The study set out to investigate the state of poly(N,N-diallyl-N,N-dimethylammonium chloride) (polyDADMAC) in aqueous solutions and the exchange reactions of polyelectrolyte anions with anions of inorganic acids, as well as to assess the effect of the acidity, basicity, and nature of Н_nX_m acids on the state of the polymer-colloidal complex (PCC) in aqueous solutions.

Methods. Potentiometry, dynamic light scattering, infrared spectroscopy, and nuclear magnetic resonance spectroscopy methods were used.

Results. The main factors affecting the state of the polyDADMAC polyelectrolyte in aqueous solutions were determined along with the characteristics of exchange processes involving anions of inorganic acids. The polymer electrolyte polyDADMAC is shown to exist in an aqueous solution in the form of impermeable polymer coils, representing polymer solvent-separated ion pairs. The Cl⁻ anion of the polyelectrolyte is exchanged for the OH⁻ ion of water or the Xⁿ⁻ anions of inorganic acids to form PCCs with polymer chain links and various counteranions. The exchange of the anions takes place mainly on the surface of the polymer coil, which limits the degree of substitution of anions and depends on the strength, nature, and basicity of the Н_nX_m acids. A relationship was found between the degree of substitution of the Xⁿ⁻ anions of the polymer coil and the strength of the resulting PCC with the enthalpy of solvation of inorganic acids Н_nX_m.

Conclusions. The polymer electrolyte polyDADMAC exists in an aqueous solution in the form of impermeable polymer coils, which are represented by polymer solvent-separated ion pairs. The exchange of the Cl⁻ anion of the polyelectrolyte for the OH⁻ ion of water or the Xn⁻ anions of inorganic acids results in the formation of PCCs with polymer chain links and various counteranions. The exchange of the anions, which takes place on the surface of the polymer coil, mainly involves the OH⁻ anion of the polyelectrolyte. A relationship was identified between the state of polymer coils of polyDADMAC, the degree of substitution of anions with different pK_a , and the degree of acid solvation. The degree of substitution of the X^n– anions of acids, which decreases with a decrease in the strength of the НnXm acid and the charge of the resulting anion in the series HClO₄ > HCl > HNO₃ > HBF₄ > HSO₄ ⁻, H2PO₄ ⁻, is characterized by a significant change in the size of the coil of the slow mode of motion of the PCC polyelectrolyte. Here, the increased diffusion coefficient from 3.0·10⁻¹³ to 1.3·10⁻¹⁰ cm²/s corresponds to a decrease in the degree of association of the links of the polymer coil of PCC in the same series. The degree of substitution of the Xn^– anions of the polymer coil and the strength of the forming PCC decrease symbatically with a decrease in the degree of solvation of inorganic acids in water.

Objectives. The creation of ion-selective electrodes (ISEs) based on rare-earth element (REE) complexes in environmentally friendly biosystems is of interest due to the increased relevance of environmental management. The work sets out to study the possibility of using REE complexes for creating ISEs sensitive to cefazolin. The created potentiometric sensors can be used for rapid determination of antibiotics in microvolume samples.

Methods. The work presents the synthesis of electrode-active REE complexes with cefazolin. In order to identify the obtained electrodeactive substances and investigate their physicochemical characteristics, the following methods were used: elemental analysis with a scanning electron microscope, infrared spectroscopy, simultaneous thermal analysis, and potentiometry.

Results. Previously unstudied complexes of cerium and lutetium with cefazolin were obtained for use as an electrode-active substance for creating ISEs. The physicochemical characteristics of the complexes were investigated. For the created ISEs, the following characteristics were studied: performance characteristics, the dependence of electrode potentials on the analyte concentration, stability, and the response time of the electrode placed in the sample under study. The created membrane electrodes are stable, have a concentration range of operation of pC 1–3, and can be used in the pH range 4–8. Testing of the selectivity of the ISEs with respect to Na⁺ and K⁺ ions showed that the electrodes are effective even in a thousandfold excess. The performance of the electrodes was tested using model systems.

Conclusions. Novel REE–cefazolin complexes were successfully demonstrated for use as electrode-active substances for the manufacture of membrane ISEs sensitive to cephalosporin antibiotics.

Objectives. Emidonol® is a veterinary drug used to treat pathological conditions associated with hypoxia in cattle. In addition tomeldonium, which is included in the Prohibited List of the World Anti-Doping Agency, the biotransformation product of Emidonol® in animals is the antioxidant and antihypoxant emoxypine, which can act as a marker of contamination of food products with the above-mentioned widely known metabolic modulator. The study set out to semiquantitatively determine emoxypine and meldonium levels, as well as to compare the excretion profiles of these substances by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) in urine samples of volunteers after receiving a single oral administration of a therapeutic dose of Brainmax® and after consuming a large amount of milk from cows that had received a prophylactic course of Emidonol®.

Methods. Sample preparation of urine samples for the determination of meldonium was carried out using the “dilute and shoot” approach. Enzymatic hydrolysis with β-glucuronidase followed by purification by solid-phase extraction was used to determine emoxypine. Identification of meldonium and emoxypine was carried out by HPLC–MS/MS under conditions of electrospray ionization with registration of positively charged ions in the selective reaction monitoring (SRM) mode for the following transitions and collision energies: for meldonium, 147.1 > 147.1 (15), 147.1 > 132.1 (17), 147.1 > 58.1 (17), 147.1 > 59.1 (17), 147.1 > 42.1 (60); for emoxypine, 138.1 > 138.1 (7), 138.1 > 123.1 (15), 138.1 > 110.1 (20), 138.1 > 95.1 (20).

Results. The possibility of simultaneous identifying meldonium and emoxypine obtained after enzymatic hydrolysis with β-glucuronidase in urine samples of volunteers after oral intake of single dose of Brainmax® and consuming a large amount of Emidonol®-contaminated milk using the HPLC–MS/MS method with different numbers and variants of SRM transitions was demonstrated. Differences in the excretion profiles of these substances were found after ingestion of large amounts of contaminated milk and a single oral dose of Brainmax® 15–18 h later and further. After taking contaminated milk 12 h or more later, emoxypine is detected in concentrations 5 or more times higher than meldonium concentrations and is excreted for a longer period of time. Conversely, after taking a single dose of Brainmax®, which contains both substances, the content of meldonium in urine samples of volunteers 15–18 h after taking it is several times higher in relation to emoxypine. The constant ratio of estimated concentrations of meldonium and emoxypine in Emidonol® was found to be approximately 1 : 2.

Conclusions. Identification of meldonium in the presence of emoxypine in urine under certain conditions can be used to distinguish contamination of food products with a prohibited metabolic modulator from intentional ingestion of real doping.