Gigopulu, Olga

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Green RP-HPLC method for impurity profile of amlodipine in tablets
(Centre for Evaluation in Education and Science (CEON/CEES), 2024)
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Godzo, Hrisanta
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Atanasovska, Biljana
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Zafirova-Gjorgievska, Marija
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<jats:p>Increased awareness of nature preservation has encouraged the introduction of the green analytical chemistry (GAC) practice concepts concerning several important aspects, including sustainable development, environmental impact, and minimum waste. The aim of this research was to contribute to the implementation of this approach for the pharmaceutical industry while retaining the crucial aspects and strict requirements of quality control of medicines. Therefore, an ethanolbased, green and robust high-performance liquid chromatography (HPLC) method for the determination of related substances of amlodipine (AML) in film-coated tablets was developed and optimized using the Design of Experiments (DoE). The chromatographic separation was performed on an RP-select B column (250 x 4.0 mm, 5 mm), using a mixture of 0.04 M sodium dihydrogen phosphate monohydrate (pH 4.0) and ethanol (60:40 % v/v) as a mobile phase. The optimized conditions provided the separation of two specified impurities (impurity D and impurity F). The selectivity of the method was confirmed using forced degradation studies. The Analytical Eco-scale approach and AGREE metrics confirmed that the method conforms to the GAC principles. The validated method was successfully applied for the determination of related substances in three samples from the market, demonstrating the applicability of the method in routine analysis.</jats:p>
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PLS based quantitative determination of insulin aspart in solution using Raman spectroscopy
(Centre for Evaluation in Education and Science (CEON/CEES), 2024)
Godzo, Hrisanta
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<jats:p>The complex structure of medicines containing polypeptide active substances requires the implementation of challenging analytical approaches, based on physicochemical methods, and, where necessary, biological assays for quality control, as well as for the detection of substandard and falsified products. Vibrational spectroscopic techniques, including Raman spectroscopy, are fast, powerful, and non-destructive techniques which, when combined with multivariate chemometric modelling, can provide specific identification, quantitative determination, and insight into the secondary structure of proteins and peptides. The aim of this study was to investigate the possibility of using Raman spectroscopy as a screening method for quantification of pharmaceutical products containing active substances with polypeptide structures. For that purpose, a model based on partial least square (PLS) analysis for quantitative determination of insulin aspart in solution was developed using Raman spectroscopy. The proposed model enables the establishment of a rapid approach for screening of the quality of formulations containing active substances with polypeptide structure, providing the selection of suspected samples that should be further analysed using routine techniques, which are time-consuming and costly.</jats:p>
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Titratable Acidity and pH of Commercial Mouthwashes: A Comprehensive Analysis
(Scientific Foundation Spiroski (publications), 2025-06-27)
Andonovska, Marija
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Kokolanski, Vlatko
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Spasovski, Spiro
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Poposki, Bojan
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Mid-infrared spectroscopy as process analytical technology tool for estimation of THC and CBD content in Cannabis flowers and extracts
(Elsevier BV, 2021-04-15)
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Stefov, Stefan
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Huck, Christian W
Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most notable Cannabis components with pharmacological activity and their content in the plant flowers and extracts are considered as critical quality parameters. The new Medical Cannabis industry needs to adopt the quality standards of the pharmaceutical industry, however, the variability of phytocannabinoids content in the plant material often exerts an issue in the inconsistency of the finished product quality parameters. Sampling problems and sample representativeness is a major limitation in the end-point testing, particularly when the expected variation of the product quality parameters is high. Therefore, there is an obvious need for the introduction of Process Analytical Technology (PAT) for continuous monitoring of the critical quality parameters throughout the production processes. Infrared spectroscopy is a promising analytical technique that is consistent with the PAT requirements and its implementation depends on the advances in instrumentation and chemometrics that will facilitate the qualitative and quantitative aspects of the technique. Our present work aims in highlighting the potential of mid-infrared (MIR) spectroscopy as PAT in the quantification of the main phytocannabinoids (THC and CBD), considered as critical quality/material parameters in the production of Cannabis plant and extract. A detailed assignment of the bands related to the molecules of interest (THC, CBD) was performed, the spectral features of the decarboxylation of native flowers were identified, and the specified bands for the acid forms (THCA, CBDA) were assigned and thoroughly explained. Further, multivariate models were constructed for the prediction of both THC and CBD content in extract and flower samples from various origins, and their prediction ability was tested on a separate sample set. Savitskzy-Golay smoothing and the second derivative of the native MIR spectra (1800-400 cm-1 region) resulted in best-fit parameters. The PLS models presented satisfactory R2Y and RMSEP of 0.95 and 3.79% for THC, 0.99 and 1.44% for CBD in the Cannabis extract samples, respectively. Similar statistical indicators were noted for the Partial least-squares (PLS) models for THC and CBD prediction of decarboxylated Cannabis flowers (R2Y and RMSEP were 0.99 and 2.32% for THC, 0.99 and 1.33% for CBD respectively). The VIP plots of all models demonstrated that the THC and CBD distinctive band regions bared the highest importance for predicting the content of the molecules of interest in the respected PLS models. The complexity of the sample (plant tissue or plant extract), the variability of the samples regarding their origin and horticultural maturity, as well as the non-uniformity of the plant material and the flower-ATR crystal contact (in the case of Cannabis flowers) were governing the accuracy descriptors. Taking into account the presented results, ATR-MIR should be considered as a promising PAT tool for THC and CBD content estimation, in terms of critical material and quality parameters for Cannabis flowers and extracts.
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Unlocking the Antidiabetic Potential of CBD: In Vivo Preclinical Studies
(MDPI AG, 2025-03-21)
Rafailovska, Elena
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Xhemaili, Elona
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Biochemical insights into cannabidiol–endocannabinoid system interactions in the regulation of metabolic pathways
(Society of Chemists and Technologists of Macedonia, 2025-12-26)
Xhemaili, Elona
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Rafailovska, Elena
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Gigopulu, Olga

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