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    Sinteza și cercetarea unor copolimeri din chitosan grefați cu ftalocianină de zinc, pentru scopuri medicinale [Articol]
    (CEP USM, 2024) Popușoi, Ana; Potlog, Tamara; Bulmaga, Petru; Sadohina, Olga; Robu, Ștefan
    In the present work, we describe new copolymers of chitosan grafted with zinc aminomethylphthalocyanine, which was obtained through the mono-(o-carboxybenzamidomethyl) hydrolysis of zinc phthalocyanine at a temperature of 170-175 ℃. Copolymers of aminomethylphthalocyanine with mass contents of 10%, 20%, and 30% of H2nCH2-PCZn were successfully synthesized, and they exhibited good solubility in water and other organic solvents. The chemical structure of the copolymers was proposed through infrared molecular absorption spectroscopy. according to their optical properties in the uV-VIs region, these water-soluble copolymers can be utilized in photodynamic therapy.
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    Synthesis of quercetin functionalized chitosan and determination of antioxidant properties [Articol]
    (2023) Gonța, Maria; Duca, Gheorghe; Sârbu, Elena; Robu, Ștefan; Mocanu, Larisa
    This paper is dedicated to the synthesis of a copolymer with reducing properties obtained by functionalizing chitosan with quercetin and determining the antioxidant activity of the derivatives obtained depending on the molar mass of the polymer. For this purpose, low molecular weight chitosan was obtained by oxidizing commercial chitosan with hydrogen peroxide and further functionalization with quercetin by the covalent grafting method. The functionalization process was performed through the following steps: functionalization of chitosan with ethyl chloroformate to increase the reactivity of the amine group to the hydroxyl group of quercetin and grafting the quercetin molecule to the synthesized intermediate. The comparative antioxidant properties of the composite obtained by grafting technical chitosan with quercetin and by grafting low molecular weight chitosan were studied by the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The obtained results indicate that a decrease in the molecular weight of chitosan contributed to its grafting with quercetin. As a result, the functionalized polymer composite acquired a higher antioxidant activity and can be successfully used to inhibit the oxidation of various organic substrates in the cosmetic, food and pharmaceutical industries.
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    METODE DE INHIBIȚIE ÎN FORMAREA NNC LA NITROZAREA MEDICAMENTELOR CU UTILIZAREA CHITOSANULUI FUNCȚIONALIZAT
    (CEP USM, 2017) Vîrlan, Valeriana
    The thesis is focused on the study of antioxidant activity of chitosan and its obtaining from chitin by different methods. The use of chitosan and chitosan functionalized with dihydroxyfumaric acid in azithromycin nitrosation to reduce the nitrite concentration in the system. At present, great importance is given to studies on the estimation of carcinogenic substances and the development of inhibition methods in the formation of N nitrosocompounds.
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    STRUCTURAL, MORPHOLOGICAL AND MAGNETIC CHARACTERIZATION OF METAL-CHITOSAN/POLY (VINYL AMINE) COMPLEXES
    (Springer Nature, 2017) Cocarta, Ana; Gutanu, Vasile; Dragan, Ecaterina
    Cu and Ni complexes of chitosan/poly(vinyl amine) (CS/PVAm) composites were prepared. The metal-CS/PVAm complexes were characterized by FT-IR spectroscopy, SEM-EDX, X-ray diffraction (XRD), and magnetic moment determination. FT-IR spectra of the metal-CS/PVAm complexes showed the characteristic bands of anhidroglucose unit were affected by the metal complexation, and new bands assigned to Me-N and Me-O bonds were observed. SEM images of the surface of metal-composite complexes show the influence of metal ion on the morphology of the complexes, the strong binding of Cu and Ni, involving most of the amino groups, leading to a dense surface structure. The chemical composition on the surface of metal-CS/PVAm complexes was determined from EDX measurements. XRD provided information about the amorphous or crystalline nature of the composite and metal-composite complexes. Using magnetic susceptibility method, the oxidation degree of metal ions from the polymer phase, the homogeneous distribution of the ligand groups from the volume of the CS/PVAm beads, and the existence of the antiferromagnetic interactions between the metal ions were determined.