TY  - JOUR
AU  - Malesević, M.
AU  - Živanović, Ljiljana
AU  - Protić, Ana
AU  - Radisić, Marina
AU  - Lausević, M.
AU  - Jović, Žarko
AU  - Zečević, Mira
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5785
AB  - The present study was designed to characterize the possible degradation products of zolpidem tartrate under various stress conditions according to International Conference on Harmonization (ICH) guidelines Q1A(R2). After exposure to light, heat, hydrolysis, and oxidation, the drug significantly degraded under photolytic and acid/base hydrolytic conditions. Degradation resulted in the formation of four key degradants. Degradation products were resolved from each other and the drug by employing an isocratic elution method on Luna C-18 column with mobile phase consisting of methanol-10 mM ammonium acetate (68.4: 31.6, v/v), wherein pH was adjusted to 5.4 with glacial acetic acid. To characterize the degradation products, a method was extended to LC-MS and a mass fragmentation pattern was established using single quad-rupole. The degradants were identified as zolpacid, oxozolpidem, zolpaldehyde, and zolpyridine. Finally, the most possible degradation mechanism of zolpidem tartrate in different environments was proposed.
PB  - Akademiai Kiado Zrt, Budapest
T2  - Acta Chromatographica
T1  - Stress Degradation Studies on Zolpidem Tartrate Using LC-DAD and LC-MS Methods
EP  - 96
IS  - 1
SP  - 81
VL  - 26
DO  - 10.1556/AChrom.26.2014.1.8
ER  - 

@article{
author = "Malesević, M. and Živanović, Ljiljana and Protić, Ana and Radisić, Marina and Lausević, M. and Jović, Žarko and Zečević, Mira",
year = "2014",
abstract = "The present study was designed to characterize the possible degradation products of zolpidem tartrate under various stress conditions according to International Conference on Harmonization (ICH) guidelines Q1A(R2). After exposure to light, heat, hydrolysis, and oxidation, the drug significantly degraded under photolytic and acid/base hydrolytic conditions. Degradation resulted in the formation of four key degradants. Degradation products were resolved from each other and the drug by employing an isocratic elution method on Luna C-18 column with mobile phase consisting of methanol-10 mM ammonium acetate (68.4: 31.6, v/v), wherein pH was adjusted to 5.4 with glacial acetic acid. To characterize the degradation products, a method was extended to LC-MS and a mass fragmentation pattern was established using single quad-rupole. The degradants were identified as zolpacid, oxozolpidem, zolpaldehyde, and zolpyridine. Finally, the most possible degradation mechanism of zolpidem tartrate in different environments was proposed.",
publisher = "Akademiai Kiado Zrt, Budapest",
journal = "Acta Chromatographica",
title = "Stress Degradation Studies on Zolpidem Tartrate Using LC-DAD and LC-MS Methods",
pages = "96-81",
number = "1",
volume = "26",
doi = "10.1556/AChrom.26.2014.1.8"
}

Malesević, M., Živanović, L., Protić, A., Radisić, M., Lausević, M., Jović, Ž.,& Zečević, M.. (2014). Stress Degradation Studies on Zolpidem Tartrate Using LC-DAD and LC-MS Methods. in Acta Chromatographica
Akademiai Kiado Zrt, Budapest., 26(1), 81-96.
https://doi.org/10.1556/AChrom.26.2014.1.8

Malesević M, Živanović L, Protić A, Radisić M, Lausević M, Jović Ž, Zečević M. Stress Degradation Studies on Zolpidem Tartrate Using LC-DAD and LC-MS Methods. in Acta Chromatographica. 2014;26(1):81-96.
doi:10.1556/AChrom.26.2014.1.8 .

Malesević, M., Živanović, Ljiljana, Protić, Ana, Radisić, Marina, Lausević, M., Jović, Žarko, Zečević, Mira, "Stress Degradation Studies on Zolpidem Tartrate Using LC-DAD and LC-MS Methods" in Acta Chromatographica, 26, no. 1 (2014):81-96,
https://doi.org/10.1556/AChrom.26.2014.1.8 . .

TY  - JOUR
AU  - Manojlović, Dragica
AU  - Radisić, Marina
AU  - Laušević, Mila
AU  - Živković, Slavoljub
AU  - Miletić, Vesna
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5704
AB  - Elution of potentially toxic substances, including monomers, from resin-based dental composites may affect the biocompatibility of these materials in clinical conditions. In addition to the amounts of eluted monomers, mathematical modeling of elution kinetics reveals composite restorations as potential chronic sources of leachable monomers. The aim of this work was to experimentally quantify elution of main cross-linking monomers from four commercial composites and offer a mathematical model of elution kinetics. Composite samples (n = 7 per group) of Filtek Supreme XT (3M ESPE), Tetric EvoCeram (Ivoclar Vivadent), Admira (Voco), and Filtek Z250 (3M ESPE) were prepared in 2-mm thick Teflon moulds and cured with halogen or light-emitting diode light. Monomer elution in ethanol and water was analyzed using high-performance liquid chromatography up to 28 days postimmersion. The mathematical model was expressed as a sum of two exponential regression functions representing the first-order kinetics law. Elution kinetics in all cases followed the same mathematical model though differences in rate constants as well as the extent of monomer elution were material-, LCU-, medium-dependent. The proposed mechanisms of elution indicate fast elution from surface and subsurface layers and up to 100 times slower monomer extraction from the bulk polymer.
PB  - Wiley-Blackwell, Hoboken
T2  - Journal of Biomedical Materials Research Part B: Applied Biomaterials
T1  - Mathematical modeling of cross-linking monomer elution from resin-based dental composites
EP  - 67
IS  - 1
SP  - 61
VL  - 101B
DO  - 10.1002/jbm.b.32815
ER  - 

@article{
author = "Manojlović, Dragica and Radisić, Marina and Laušević, Mila and Živković, Slavoljub and Miletić, Vesna",
year = "2013",
abstract = "Elution of potentially toxic substances, including monomers, from resin-based dental composites may affect the biocompatibility of these materials in clinical conditions. In addition to the amounts of eluted monomers, mathematical modeling of elution kinetics reveals composite restorations as potential chronic sources of leachable monomers. The aim of this work was to experimentally quantify elution of main cross-linking monomers from four commercial composites and offer a mathematical model of elution kinetics. Composite samples (n = 7 per group) of Filtek Supreme XT (3M ESPE), Tetric EvoCeram (Ivoclar Vivadent), Admira (Voco), and Filtek Z250 (3M ESPE) were prepared in 2-mm thick Teflon moulds and cured with halogen or light-emitting diode light. Monomer elution in ethanol and water was analyzed using high-performance liquid chromatography up to 28 days postimmersion. The mathematical model was expressed as a sum of two exponential regression functions representing the first-order kinetics law. Elution kinetics in all cases followed the same mathematical model though differences in rate constants as well as the extent of monomer elution were material-, LCU-, medium-dependent. The proposed mechanisms of elution indicate fast elution from surface and subsurface layers and up to 100 times slower monomer extraction from the bulk polymer.",
publisher = "Wiley-Blackwell, Hoboken",
journal = "Journal of Biomedical Materials Research Part B: Applied Biomaterials",
title = "Mathematical modeling of cross-linking monomer elution from resin-based dental composites",
pages = "67-61",
number = "1",
volume = "101B",
doi = "10.1002/jbm.b.32815"
}

Manojlović, D., Radisić, M., Laušević, M., Živković, S.,& Miletić, V.. (2013). Mathematical modeling of cross-linking monomer elution from resin-based dental composites. in Journal of Biomedical Materials Research Part B: Applied Biomaterials
Wiley-Blackwell, Hoboken., 101B(1), 61-67.
https://doi.org/10.1002/jbm.b.32815

Manojlović D, Radisić M, Laušević M, Živković S, Miletić V. Mathematical modeling of cross-linking monomer elution from resin-based dental composites. in Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2013;101B(1):61-67.
doi:10.1002/jbm.b.32815 .

Manojlović, Dragica, Radisić, Marina, Laušević, Mila, Živković, Slavoljub, Miletić, Vesna, "Mathematical modeling of cross-linking monomer elution from resin-based dental composites" in Journal of Biomedical Materials Research Part B: Applied Biomaterials, 101B, no. 1 (2013):61-67,
https://doi.org/10.1002/jbm.b.32815 . .

TY  - JOUR
AU  - Jović, Žarko
AU  - Živanović, Ljiljana
AU  - Protić, Ana
AU  - Radisić, Marina
AU  - Laušević, Mila
AU  - Malešević, Marija
AU  - Zečević, Mira
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5699
AB  - Torasemide was subjected to forced degradation studies. Stress conditions were varied concerning hydrolysis (acid, base, and neutral), oxidation, photolysis, and thermal degradation in order to identify the potential degradation products and consequently establish the possible degradation pathways and intrinsic stability of the drug. The study was performed according to ICH guidelines and drug was found to be relatively stable in the solid form. It showed that torasemide degraded significantly under acidic, neutral and alkaline conditions and resulted in formation of degradation product R2. When temperature was increased the degradation was accelerated. Also, the drug showed slight instability under extreme oxidative stress conditions which resulted in formation of two degradation products in total. The drug and degradation products have been separated employing gradient elution method on Zorbax SB C-18 analytical column. To characterize the degradation products LC-MSn was applied. The mass fragmentation pattern was established using single quadrupole and ion trap mass analyzers. Finally, the most possible degradation mechanism of torasemide in different experimental conditions was proposed.
PB  - Taylor & Francis Inc, Philadelphia
T2  - Journal of Liquid Chromatography & Related Technologies
T1  - Forced degradation study of torasemide: Characterization of its degradation products
EP  - 2094
IS  - 15
SP  - 2082
VL  - 36
DO  - 10.1080/10826076.2012.712932
ER  - 

@article{
author = "Jović, Žarko and Živanović, Ljiljana and Protić, Ana and Radisić, Marina and Laušević, Mila and Malešević, Marija and Zečević, Mira",
year = "2013",
abstract = "Torasemide was subjected to forced degradation studies. Stress conditions were varied concerning hydrolysis (acid, base, and neutral), oxidation, photolysis, and thermal degradation in order to identify the potential degradation products and consequently establish the possible degradation pathways and intrinsic stability of the drug. The study was performed according to ICH guidelines and drug was found to be relatively stable in the solid form. It showed that torasemide degraded significantly under acidic, neutral and alkaline conditions and resulted in formation of degradation product R2. When temperature was increased the degradation was accelerated. Also, the drug showed slight instability under extreme oxidative stress conditions which resulted in formation of two degradation products in total. The drug and degradation products have been separated employing gradient elution method on Zorbax SB C-18 analytical column. To characterize the degradation products LC-MSn was applied. The mass fragmentation pattern was established using single quadrupole and ion trap mass analyzers. Finally, the most possible degradation mechanism of torasemide in different experimental conditions was proposed.",
publisher = "Taylor & Francis Inc, Philadelphia",
journal = "Journal of Liquid Chromatography & Related Technologies",
title = "Forced degradation study of torasemide: Characterization of its degradation products",
pages = "2094-2082",
number = "15",
volume = "36",
doi = "10.1080/10826076.2012.712932"
}

Jović, Ž., Živanović, L., Protić, A., Radisić, M., Laušević, M., Malešević, M.,& Zečević, M.. (2013). Forced degradation study of torasemide: Characterization of its degradation products. in Journal of Liquid Chromatography & Related Technologies
Taylor & Francis Inc, Philadelphia., 36(15), 2082-2094.
https://doi.org/10.1080/10826076.2012.712932

Jović Ž, Živanović L, Protić A, Radisić M, Laušević M, Malešević M, Zečević M. Forced degradation study of torasemide: Characterization of its degradation products. in Journal of Liquid Chromatography & Related Technologies. 2013;36(15):2082-2094.
doi:10.1080/10826076.2012.712932 .

Jović, Žarko, Živanović, Ljiljana, Protić, Ana, Radisić, Marina, Laušević, Mila, Malešević, Marija, Zečević, Mira, "Forced degradation study of torasemide: Characterization of its degradation products" in Journal of Liquid Chromatography & Related Technologies, 36, no. 15 (2013):2082-2094,
https://doi.org/10.1080/10826076.2012.712932 . .

TY  - JOUR
AU  - Manojlović, Dragica
AU  - Radisić, Marina
AU  - Vasiljević, Tatjana
AU  - Živković, Slavoljub
AU  - Laušević, Mila
AU  - Miletić, Vesna
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5640
AB  - Objectives. To study monomer elution from four resin-based composites (RBCs) cured with different light sources. Methods. Twenty-eight premolars were randomly allocated to four groups. Standardized cavities were prepared and restored with a nanohybrid (Filtek Supreme XT or Tetric EvoCeram), an ormocer (Admira) or a microhybrid RBC (Filtek Z250) which served as control. Buccal restorations were cured with a halogen and oral restorations with an LED light-curing unit. Elution of diurethane dimethacrylate (UDMA), Bisphenol A diglycidylether methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) was analyzed using high-performance liquid chromatography (HPLC) 1h to 28 days post-immersion in 75% ethanol. Data were analyzed using multivariate and repeated measures analysis of variance (alpha = 0.05). Results. The greatest elution of UDMA and BisGMA occurred from Tetric EvoCeram and the least from Filtek Z250 (p  lt  0.05). LED and halogen light-curing units gave similar results for all RBCs (p > 0.05) except Tetric EvoCeram which showed greater elution for the LED unit (p  lt  0.05). TEGDMA was below the limit of quantification. HEMA eluted in similar concentrations from Filtek Supreme and Tetric EvoCeram (p > 0.05). Significance. : The two nanohybrid RBCs eluted more cross-linking monomers than the ormocer and the control microhybrid RBC. Continuous elution over 28 days indicates that RBCs act as a chronic source of monomers in clinical conditions. Light source may affect monomer elution since differences were found for one out of four RBCs. Mathematical models for elution kinetics of UDMA and BisGMA indicated two elution mechanisms.
PB  - Elsevier Sci Ltd, Oxford
T2  - Dental Materials
T1  - Monomer elution from nanohybrid and ormocer-based composites cured with different light sources
EP  - 378
IS  - 4
SP  - 371
VL  - 27
DO  - 10.1016/j.dental.2010.11.017
ER  - 

@article{
author = "Manojlović, Dragica and Radisić, Marina and Vasiljević, Tatjana and Živković, Slavoljub and Laušević, Mila and Miletić, Vesna",
year = "2011",
abstract = "Objectives. To study monomer elution from four resin-based composites (RBCs) cured with different light sources. Methods. Twenty-eight premolars were randomly allocated to four groups. Standardized cavities were prepared and restored with a nanohybrid (Filtek Supreme XT or Tetric EvoCeram), an ormocer (Admira) or a microhybrid RBC (Filtek Z250) which served as control. Buccal restorations were cured with a halogen and oral restorations with an LED light-curing unit. Elution of diurethane dimethacrylate (UDMA), Bisphenol A diglycidylether methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) was analyzed using high-performance liquid chromatography (HPLC) 1h to 28 days post-immersion in 75% ethanol. Data were analyzed using multivariate and repeated measures analysis of variance (alpha = 0.05). Results. The greatest elution of UDMA and BisGMA occurred from Tetric EvoCeram and the least from Filtek Z250 (p  lt  0.05). LED and halogen light-curing units gave similar results for all RBCs (p > 0.05) except Tetric EvoCeram which showed greater elution for the LED unit (p  lt  0.05). TEGDMA was below the limit of quantification. HEMA eluted in similar concentrations from Filtek Supreme and Tetric EvoCeram (p > 0.05). Significance. : The two nanohybrid RBCs eluted more cross-linking monomers than the ormocer and the control microhybrid RBC. Continuous elution over 28 days indicates that RBCs act as a chronic source of monomers in clinical conditions. Light source may affect monomer elution since differences were found for one out of four RBCs. Mathematical models for elution kinetics of UDMA and BisGMA indicated two elution mechanisms.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Dental Materials",
title = "Monomer elution from nanohybrid and ormocer-based composites cured with different light sources",
pages = "378-371",
number = "4",
volume = "27",
doi = "10.1016/j.dental.2010.11.017"
}

Manojlović, D., Radisić, M., Vasiljević, T., Živković, S., Laušević, M.,& Miletić, V.. (2011). Monomer elution from nanohybrid and ormocer-based composites cured with different light sources. in Dental Materials
Elsevier Sci Ltd, Oxford., 27(4), 371-378.
https://doi.org/10.1016/j.dental.2010.11.017

Manojlović D, Radisić M, Vasiljević T, Živković S, Laušević M, Miletić V. Monomer elution from nanohybrid and ormocer-based composites cured with different light sources. in Dental Materials. 2011;27(4):371-378.
doi:10.1016/j.dental.2010.11.017 .

Manojlović, Dragica, Radisić, Marina, Vasiljević, Tatjana, Živković, Slavoljub, Laušević, Mila, Miletić, Vesna, "Monomer elution from nanohybrid and ormocer-based composites cured with different light sources" in Dental Materials, 27, no. 4 (2011):371-378,
https://doi.org/10.1016/j.dental.2010.11.017 . .