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    Development of thermo/pH-responsive chitosan coated pectin-graft-poly(N, N-diethyl acrylamide) microcarriers
    (Elsevier Sci Ltd, 2019) Isiklan, Nuran; Tokmak, Seyma
    Pectin based micro/nanocarriers display promising properties for biomedical applications. In this study, thermo/pH-responsive chitosan coated pectin-graft-poly(N,N-diethyl acrylamide) (Pec-g-PDEAAm/CS) microcarriers containing 5-Fluorouracil (5-FU) as a model drug were developed. The structure, thermal stability and surface morphology of 5-FU-loaded microcarriers were investigated using FTIR, XRD, DSC and SEM. Microcarrier formulations were fabricated by varying grafting yield, drug/copolymer ratio, chitosan, and crosslinking agent concentrations. The effect of these parameters on swelling degree and 5-FU release was explored. It was observed that the grafting of pectin with poly(N,N-diethyl acrylamide) ensured sustained/controlled and thermo/pH responsive release of 5-FU. Besides, in vitro cytotoxicity results displayed that Pec-g-PDEAAm/CS microcarriers had good biocompatibility. Results illustrated that 5-FU release and swelling degree of the microcarriers were greatly controlled by especially chitosan shell, 5-FU/copolymer ratio and crosslink density. Therefore, based on the findings the developed thermo/pH-responsive Pec-g-PDEAAm/CS microcarriers might be considered as a promising carrier for controlled drug delivery.
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    Microwave based synthesis and spectral characterization of thermo-sensitive poly(N,N-diethylacrylamide) grafted pectin copolymer
    (Elsevier Science Bv, 2018) Isiklan, Nuran; Tokmak, Seyma
    The functionalization of polysaccharides with synthetic polymers has attracted great attention owing to its application in many industrial fields. The aim of this work was to study the impact of pectin functionalization with N, N-diethylacrylamide (DEAAm). Pectin was modified via microwave-induced graft copolymerization of DEAAm using ceric ammonium nitrate (CAN) and N,N,N',N'-tetramethylethylenediamine (TEMED). FTIR, C-13 NMR, DSC/TGA, XRD, and SEM techniques were used to verify the structure of graft copolymers. Various reaction conditions such as microwave irradiation time, temperature, microwave power, monomer, initiator, and TEMED concentrations were investigated to get a maximum grafting yield of 192%. Lower critical solution temperatures (LCST) of graft copolymers were determined by UV spectroscopy. Graft copolymers were found to be thermo-sensitive, with LCST of 31 degrees C and high thermal resistance. Biocompatibility test of copolymers showed that copolymers were not cytotoxic to L929 fibroblasts cells and can be used as a biomaterial. (C) 2018 Elsevier B.V. All rights reserved.