SYNTHESIS AND PROPERTIES OF Sr-CONTAINING TRYCALCIUM PHOSPHATE

Sr -замещенный трикальцийфосфат был получен методом осаждения из водных растворов. Синтетические твердые фазы исследовали с помощью рентгеннофазового анализа, ИК-Фурье спектроскопии, сканирующей электронной микроскопии, энергодисперсионного анализа. Надосадочная жидкость была исследована на наличие ионов Ca и PO для вычисления Са/Р соотношения. Выявлено, что ионы стронция входят в состав трикальцийфосфата, однако не изменяют его фазовый состав. Добавление ионов стронция в исходный раствор способствует уменьшению размеров кристаллитов и увеличению их пористости. Данные по энергодисперсионному анализу подтвердили, что ионы стронция входят в состав образцов ТКФ. Но при увеличении их концентрации, полного замещения ионов кальция на ионы стронция в структуре ТКФ не происходит. При изучении биорезорбируемости полученных образцов с помощью прямой потенциометрии установлено, что образцы, содержащие ионы стронция в своем составе, имеют меньшее значение скорости резорбции. При этом, наибольшие значения скорости растворения фиксируются в кислых средах. Sr -substituted tricalcium phosphate was obtained by precipitation from aqueous solutions. Synthetic solid phases were investigated using X-ray phase analysis, IR spectroscopy, scanning electron microscopy, energy dispersive analysis. The supernatant was examined for the presence of Ca and PO4 ions to calculate the Ca/P ratio. It was revealed that strontium ions are part of tricalcium phosphate, but do not change its phase composition. The addition of strontium ions to the initial solution contributes to a decrease in the size of crystallites and an increase in their porosity. When studying the bioresorbability of the obtained samples using direct potentiometry, it was found that the samples containing strontium ions in their composition have a lower value of the rate of resorption. Energy dispersive analysis data confirmed that strontium ions are included in the composition of TCP samples. But with an increase in their concentration, complete replacement of calcium ions with strontium ions in the TCP structure does not occur. At the same time, the highest values of the dissolution rate are recorded in acidic media.

REDOX PROCESSES IN THE REACTIONS OF N-ARYLSULFONYL-1,4-NAPHTНOQUINONЕIMINES WITH CERTAIN NUCLEOPHILES

Quinone-hydroquinone pairs are prototypes of organic redox systems, and studies of the electrochemical behavior of these compounds are of great interest for research. Electrochemical behavior associated with the equilibrium of electron-proton transfer provides information about the molecular structure and environment of the process. Apart from chemical aspects, quinones play an important role in the biochemistry of living cells. Quinone derivatives, used as drugs for several types of human cancers, have been found to have their biological activity related to their redox behavior. Quinoneimines-aminophenols form similar pairs. In nucleophilic addition reactions of N‑substituted p-quinoneimines, parallel redox processes are often observed, and the higher the redox potential of quinoneimine, the greater the likelihood of such processes. Naphthoquinoneimines with aromatic amines and acylhydrazines follow the scheme of 1,4-addition, but as reaction products are oxidized products -4-arylsulfonylamido‑2-arylamino(2-aroylamino)-1,4-naphthoquinoneimines. The oxidant may be the original naphthoquinoneimine and oxygen. Studies have shown that oxygen in the reaction of 1,4-naphthoquinoneimines with acylhydrazines is the only oxidant that oxidizes the product of 1,4-addition, as evidenced by the study of redox potentials. Both oxidized and reduced form of the compounds, as naphthoquinoneimine and the corresponding aminonaphthol, are used to determine the redox potential by direct potentiometry. Due to the instability of the reduced form in the case of the pair naphthoquinoneimine-aminonaphthol, we used only the reduced form, which is oxidized in the cell by oxygen. The redox potential of the naphthoquinoneimine-aminonaphthol galvanic pair was determined as the average value between the potential Emax, which was established in the system upon complete oxidation of the starting substance, that is, when only naphthoquinone imine remains in the system, and the potential Emin, which was registered at the beginning of the process in the system with the reduced form – the corresponding aminonaphthol. This is the method of direct potentiometry in the variant of the middle potential.

Which laboratory technique is used for the blood sodium analysis in clinical research? A systematic review

Background Circulating sodium is analyzed by flame spectrometry and indirect or direct potentiometry. The differences between estimates returned by the three techniques are often relevant. It is unknown whether peer-reviewed international publications focusing on this parameter provide information about the technique. Objectives of the study were to ascertain if information about the employed technique is provided. Content A search in the National Library of Medicine for articles whose title contains “hyponatr[a]emia” was performed. We restricted the search to clinical reports including 10 or more humans published in the 2013–2015 and 2017–2019 periods. Authors of papers not reporting the technique were contacted to obtain this information. The study design and journal quartile ranking of each article were also evaluated. Summary For the final analysis, we included 361 articles (2013–2015, n=169; 2017–2019, n=192). Information about the laboratory technique was given in 61(17%) articles. Thanks to our inquiry, we collected this information for 116(32%) further reports. Indirect potentiometry was the most frequently used technique, followed by direct potentiometry. Spectrometry was used in a small minority of studies. Study design, journal ranking and study period did not modulate the mentioned frequency. Outlook Most articles focusing on hyponatremia do not provide information on the laboratory technique. This parameter is nowadays analyzed by indirect or, less frequently, direct potentiometry. The figures are similar for high and low impact factor journals and for the 2013–2015 and the 2017–2019 periods. Many authors, reviewers and editors likely assume that the results of this parameter are not influenced by the technique.

A218 A CASE REPORT OF PSEUDOHYPONATREMIA IN CHOLESTATIC LIVER DISEASE

Background True hyponatremia in the setting of cholestatic liver disease may signify cirrhosis with fluid overload, and is therefore an ominous sign of deteriorating liver function. In pediatric liver transplant candidates, it is associated with increased waitlist mortality. Pseudohyponatremia however, is a falsely low measurement of plasma sodium when measured by indirect potentiometry. Pseudohyponatremia secondary to hypercholesterolemia is a phenomenon that occurs due to a reduced aqueous fraction of the plasma when levels of cholesterol or triglycerides are greatly elevated. Severe hypercholesterolemia due to Lipoprotein X accumulation may be the cause of pseudohyponatremia in biliary obstruction or cholestasis. Aims To describe a case of pseudohyponatremia secondary to hypercholesterolemia in an infant with Alagille syndrome (ALGS) and cholestatic liver disease. Methods This 7 month-old male with ALGS (confirmed JAGGED1 mutation) and severe cholestasis, failure to thrive, and pruritus, developed new-onset progressive hyponatremia as low as 121 mmol/L at an outside institution. He was therefore transferred to our center for liver transplant assessment due to concerns of progressive liver dysfunction and for management of the hyponatremia. Results Upon admission, the patient was jaundiced but euvolemic, with no evidence of ascites or peripheral edema. Laboratory work drawn at our institution showed conjugated bilirubin of 180 mmol/L, ALT 300 U/L, AST 250 U/L, and GGT 1200 U/L. INR was 1.1 and albumin of 35 g/L. The cholesterol was elevated above 16.8 mmol/L, with high triglycerides 2.68 mmol/L, and the serum appeared visibly lipemic. The sodium level was 138 mmol/L as measured by direct potentiometry due to the visible lipemia. The osmolality of 288 mmol/kg was normal with a normal osmolar gap. Urine osmolality and sodium were also normal. He underwent routine evaluation and was listed for a liver transplant due to the profound cholestasis and growth failure. Conclusions Pseudohyponatremia is an important entity to recognize when caring for patients with cholestatic liver disease and hyponatremia. Both direct potentiometry and indirect potentiometry are currently used for sodium testing in blood in biochemistry laboratories. These measurement techniques show good agreement as long as protein and lipid concentrations in blood are normal, however, hyperlipidemia is a well-recognized cause for error in sodium estimation. It is therefore imperative to evaluate apparent hyponatremia correctly, especially when the patient appears euvolemic clinically and by normal serum osmolality. In this clinical setting, pseudohyponatremia is the likely cause and a workup should be carried out to identify possible underlying etiologies, the most probable being hypercholesterolemia. Failure to recognize this phenomenon may lead to unnecessary and potentially harmful treatments and interventions. Funding Agencies None

ION-SELECTIVE ELECTRODE FOR DETERMINATION OF METFORMIN IN PHARMACEUTICAL PREPARATIONS

Описана конструкция и электроаналитические характеристики ионселективного электрода (ИСЭ) для количественного определения метформина. В качестве электродноактивных соединений в ИСЭ были использованы ионные ассоциаты метформина с фосфорновольфрамовой(ФВК), фосфорномолибденовой(ФМК) и кремний вольфрамовой кислотами (КВК). Проведено потенциометрическое определение метформина в фармацевтических препаратах. The construction and electroanalytical characteristics of ion-selective electrode (ISE) for metformin are described. Ion pair of metformin with heteropolyacids were tested as electroactive materials for ionometric sensor controls. The ISE was used for direct potentiometry of metformin.

Reference Intervals for Potassium, Sodium and Chloride among Libyan Healthy People

Background: In Libya, all laboratories use reference intervals (RIs) derived from other country’s populations, which differ from Libyan population in many aspects such as daily habits and race. Due to these differences, it is assumed that those RIs are not applicable to Libyans. Aim: The aim of this study was to establish RIs of sodium, potassium and chloride in serum of Libyan people. Materials and Methods: Two hundred and fifty-seven blood specimens of healthy people (males and females) were collected using venipuncture untreated tubes. The specimens were centrifuged for 15 minutes and the obtained sera were analyzed for their content of sodium, potassium and chloride using direct potentiometry method. Results and Discussion: The non-parametric percentile method was applied to establish the RIs of sodium, chloride and potassium, which were found to be: 135-143.3; 103-110; 3.7-5.2 mmol/L, respectively. There were no considerable differences in lower limits and/or upper limits of all established RIs between males and females, except that the upper limit of Cl− for females was slightly higher than that for males. Conclusion: As there are evident regional differences in RIs, the established RIs in this study will be more favorable in Libya than those listed in the manufacturer’s kit or those adopted from other population-based references.

Preparation and Description of Potentiometric Electrode for the Limitation of Sulbutamol Sulphate

A new sulbatamol sulphate SBS membrane electrode was prepared that utilizing for its determination ; depend on the forming of the association complex ion of sulbatamol sulphate by the phosphotungstate counter anion deposed in poly vinyl chloride PVC polymer, by use a (Di-n- Octyl Phenyl Phthalate)(Dopp) as the plastizier substance, in membrane.The features properties as well as the behavior of it .The new electrode have been elaborated. The concentrations of medicine by utillizing This sensor show a fast, stable, near-Nernstian response in the range (1x10-1-1x10-6) mol/ L were determined with correlation coefficient of about (r = 0.9991) and with of a relative standard about 0.416 additionally deviation relative standard error of 1.710  %.pot The nernast linearity slop was founded and it is equal to 28.9 mV/decade and the detection limit was 4.1 x 10-6 mol/ L.The electrode selectivity coefficient Ki,j was calculated, in the existence of several interferences cations with confirmed medicine solutions. It was found the pH range response is in the range of (3 -7), with the response time of (30 – 116) sec. for various  concentrations at room temperture , the lifetime for  electrode was found to be more than 21 days. The electrode was successfully used for potentiometric limitation of sulbatamol sulphate in several pharmaceutical drugs by using direct potentiometry.

Sn-Containing Oxide Coatings: Formation, Composition, Electroanalytical and Catalytic Properties

Sn-containing oxide coatings were prepared via plasma electrolytic oxidation (PEO) of Ti plate in the electrolytes with [SnII-EDTA]2- complex anions or SnO2 particles in the anode and anodic-cathodic modes. The coatings formed in electrolyte with SnO2 particles stabilized by SAS contain SnO2 and Sn0. In the electrolyte with [Sn-EDTA]2- complex anions, the SnO2-containing coatings were formed in the anodic mode while Sn0-containing ones were obtained in the anodic-cathodic mode. SnO2-containing structures formed in the electrolytes with [Sn-EDTA]2- anions are shown to be active in catalytic oxidation of CO into CO2 at temperatures above 350 °C. They can be the basis for the preparation of both carriers of catalytically active compounds and catalysts for redox reactions. Potentiometric tests showed that the Sn-containing PEO layers on titanium exhibit the most characteristic pH function for the metal oxide electrodes in the direct potentiometry and acid-base titration.