Institute of Chemistry

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    Pharmacokinetics of different selenium supplements in healthy individuals and patients with autoimmune thyroiditis after oral administration
    (Society of Chemists and Technologists of Macedonia, 2025-06-24)
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    Stafilov, Trajče
    Selenium is essential for the function of key selenoproteins such as glutathione peroxidase, thiore-doxin reductase, and iodothyronine deiodinase, which have antioxidant properties and support thyroid hormone metabolism. Due to the low selenium content in European soils – particularly in the Southeast-ern regions, supplementation is often recommended, especially for conditions like Hashimoto's thyroidi-tis. However, careful consideration of selenium dosage and pharmacokinetics is crucial, as the margin be-tween essential and toxic levels is very narrow. The aim of this study was to investigate the pharmacoki-netics of selenium absorption and plasma concentration following oral administration of various selenium doses and chemical forms, both in the short and long term, in healthy individuals and patients with auto-immune thyroiditis. Selenium concentrations in blood plasma were measured using electrothermal atomic absorption spectrometry (ETAAS). The study found that L-selenomethionine is absorbed more efficiently than inorganic sodium selenite, with peak plasma concentrations reached and sustained within 6 – 8 hours. Selenium levels remained elevated 48 hours after ingestion compared to baseline. At a daily dose of 200 μg of selenium as L-selenomethionine, plasma selenium concentrations increased by approximate-ly 30 %, and by about 25 % at 100 μg/day, relative to the initial value. Long-term studies showed that plasma selenium concentrations rose significantly after the first month of supplementation, with a slower increase in subsequent months. After supplementation ended, selenium levels declined rapidly. Interest-ingly, no significant differences in selenium absorption or excretion were observed between patients with Hashimoto's thyroiditis and healthy controls.
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    Infrared and Raman spectra of racemic ibuprofen sodium dihydrate – Spectra-structure correlations
    (Elsevier BV, 2025-10)
    Cvetkovska Bogatinovska, E.
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    Najkov, K.
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    Petrushevski, Gj.
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    Koleva, V.
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    Lipoxygenase Inhibitory Activity and Prostate Cancer Cytotoxicity of In Situ- and In Vitro-Cultivated Balkan Endemic Sideritis scardica Griseb
    (MDPI AG, 2025-10-25)
    Danova, Kalina
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    Stoyanova, Elena
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    Alipieva, Kalina
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    Sideritis scardica Griseb., a Balkan endemic species traditionally used for respiratory conditions and wound-healing, was investigated for its 15-lipoxygenase (15-LOX) inhibitory and cytotoxic activities in relation to its phenolic composition. Aerial parts from the wild-collected and in vitro-cultivated plant were successively extracted with hexane, chloroform, and methanol and the methanol extract was further fractionated into ethyl acetate, butanol, and water fractions. This study presents the first combined evaluation of LOX inhibition and cytotoxicity against prostate cell lines WPMY-1 (normal epithelial fibroblast/myofibroblast), PC-3 (epithelial adenocarcinoma, Grade IV), and LNCaP (epithelial carcinoma) and detailed phytochemical profiles of wild-collected and in vitro-cultivated S. scardica. The phytochemical analysis revealed distinct profiles: increased LOX-inhibition activity was related to a higher phenylethanoid/flavone glycoside ratio, while PC cytotoxicity was rather related to flavone glycoside domination in the plant preparations. The cytotoxic effect of the in vitro-obtained preparations was characterized by a marked selectivity when comparing their effects on WPMY-1, PC-3 and LNCaP cells. To our knowledge, this is the first report linking phenylethanoid/flavone glycoside profiles of in situ and in vitro S. scardica plants with dual LOX-inhibitory and anti-prostate cancer activities, supporting the plant’s potential as a sustainable source of bioactive compounds.
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    LC-HRMS and NMR study of the esterification products of ibuprofen with solketal: Formation, isolation and identification
    (Society of Chemists and Technologists of Macedonia, 2025-12-24)
    Jakimovska Pokupec, Viktorija
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    Popova, Milena
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    Bankova, Vassya
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    Ibuprofen is a widely used non-steroidal anti-inflammatory drug dispensed in tablets, capsules, suspensions, oral solutions, creams, and gels. Ibuprofen's poor water solubility and gastrointestinal side-effects present ongoing formulation challenges. Alcoholic excipients are often employed to enhance solubility and minimise adverse effects. Solketal (1,2-isopropylidene glycerol), a ketal produced by the condensation of glycerol with acetone, offers further versatility as an excipient due to its free hydroxyl group, which enables esterification reactions with acidic active pharmaceutical ingredients like ibuprofen. Introducing any excipient, especially in direct contact with the active pharmaceutical ingredient, necessitates careful evaluation of potential drug–excipient interactions, as these can alter the drug's physicochemical properties and impact clinical performance. Chromatographic techniques coupled with mass spectrometry and nuclear magnetic resonance spectroscopy remain essential for identifying and characterising related and degradation products in pre-formulation studies. In this study, we investigated the esterification of ibuprofen with solketal to identify possible interaction products. Two major compounds were isolated and thoroughly characterised by MS and NMR, confirming their chemical structures: 1-mono-glycerol ester of ibuprofen and ibuprofen-solketal-ester, which contained a 1,3-dioxolane ring. This finding highlights the importance of comprehensive analytical evaluation of drug–excipient interactions during formulation development, as these can affect drug stability and performance.
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    Stabilizing latent fingermarks developed with iodine fuming: A new method
    (Elsevier BV, 2025-05-17)
    Singh, Varinder
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    Mandal, P.
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    Sasho, Stojkovikj
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    Slobodan, Oklevski
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    Evaluating green and sustainable chemistry education through students’ interventions
    (Society of Chemists and Technologists of Macedonia, 2025-05-28)
    Nikolovski, Daniel
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    This study explores the integration of green and sustainable chemistry into educational curricula and its impact on students' knowledge, motivation, and perceptions. The research aimed to evaluate whether activities centered on green and sustainable chemistry improve students' academic performance and foster awareness of sustainability concepts. Conducted between April and June 2024 in three primary schools in N. Macedonia, the study involved 211 8th grade students, divided into a control group and an experimental group. While the control group followed standard les-sons, the experimental group participated in specific activities integrated into the topic "Introduction to Organic Chemistry." A mixed-methods approach was employed, combining quantitative tools such as the conceptual knowledge test and the activity perception questionnaire, alongside qualitative methods like focus groups and semi-structured inter-views. The conceptual knowledge test assessed students' academic achievements, while the activity perception questionnaire evaluated their perceptions of the activities. The results showed no significant difference in academic performance between the two groups. However, the activity perception questionnaire revealed that students in the experimental group found the activities engaging, valuable, and effective in enhancing their understanding of green and sustainable chemistry concepts. Qualitative data further indicated a preference for interactive learning methods like re-search, games, and experiments, which fostered greater motivation and collaboration among students. This study under-scores the importance of integrating green and sustainable chemistry into curricula to promote environmental awareness and sustainable practices. These findings provide insights into effective teaching strategies and support the inclusion of green and sustainable chemistry in educational policies to equip students for global environmental challenges.
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    Semi-Quantitative Characterization of Volatile Organic Compounds in Indoor and Outdoor Air Using Passive Samplers: A Case Study of Milan, Italy
    (MDPI AG, 2025-09-16)
    Mula, Vllaznim
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    Zeneli, Lulzim
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    Mehmeti, Valbonë
    This study presents a semi-quantitative characterization of volatile organic compound (VOC) concentrations and their emission sources in indoor and outdoor environments across four residential and laboratory sites in Milan, Italy, during the summer of 2024. Radiello® passive samplers (Fondazione Salvatore Maugeri in Padova, Italy) were employed for VOC collection, followed by gas chromatography–mass spectrometry analysis. The semi-quantitative mean total VOC (TVOC) concentration was 220.8 ± 195.4 µg/m3 for the outdoor air and slightly higher at 243.6 ± 134.3 µg/m3 for the indoor air, resulting in an indoor-to-outdoor relative ratio of 1.10. The outdoor VOC profile was dominated by hydrocarbons, accounting for 80.3% ± 4.6% (173.2 ± 143.8 µg/m3) of TVOCs, followed by aromatic hydrocarbons at 13.3% ± 5.5% (37.2 ± 49.7 µg/m3). Indoors, hydrocarbons also predominated, representing 34.1% ± 15.2% (95.2 ± 80.1 µg/m3) of the TVOCs, followed by terpenes at 20.7% ± 15.5% (49.0 ± 46.4 µg/m3). Other VOC groups contributed smaller fractions in both environments. The emission profiles from cleaning and personal care products were assessed semi-quantitatively to determine their relative percentage contributions to the indoor VOCs. Source attribution was further supported by diagnostic relative ratios—benzene/toluene, toluene/benzene, and (m + p)-xylene/ethylbenzene—which provided insight into dominant emission sources and photochemical aging.
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    Elementary, my dear Watson! The making of a collection of the natural elements
    (Society of Chemists and Technologists of Macedonia, 2022-06-21)
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    <jats:p>A unique collection of samples of the chemical elements has been created and displayed at our Institute of Chemistry. Although whole collections are now commercially available, we decided to use, as much as possible, samples from local resources. The general idea was for each item to have a story, making it more interesting for the students and visitors. We were able to acquire elemental samples mined in Macedonia. Other samples were from our student and research labs, as well as donations from colleagues, and the rest were obtained from commercial sources. A web page was created with all the information on each sample, some of them containing videos. Next to the noble gases, mini Tesla coils were mounted to light up the gases.</jats:p>