TY  - JOUR
AU  - Jauković, Valentina
AU  - Krajišnik, Danina
AU  - Daković, Aleksandra
AU  - Damjanović, Ana
AU  - Krstić, Jugoslav
AU  - Stojanović, Jovica
AU  - Čalija, Bojan
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3796
AB  - The functionality of halloysite (Hal) nanotubes as drug carriers can be improved by lumen enlargement and polymer modification. This study investigates the influence of selective acid etching on Hal functionalization with cationic biopolymer chitosan. Hal was subjected to lumen etching under mild conditions, loaded under vacuum with nonsteroidal antiinflammatory drug aceclofenac, and incubated in an acidic solution of chitosan. The functionality of pristine and etched Hal before and upon polymer functionalization was assessed by ζ-potential measurements, structural characterization (FT-IR, DSC and XRPD analysis), cell viability assay, drug loading and drug release studies. Acid etching increased specific surface area, pore volume and pore size of Hal, decreased ζ-potential and facilitated binding of the cationic polymer. XRPD and DSC analysis revealed crystalline structure of etched Hal. Successful chitosan binding and drug entrapment were further confirmed by FT-IR and DSC studies. XRPD showed surface polymer binding. DSC and FT-IR analyses confirmed the presence of the entrapped drug in its crystalline form. Drug loading was increased for ≈81% by selective lumen etching. Slight decrease of drug content occurred during chitosan functionalization due to aceclofenac diffusion in the polymer solution. The drug release was more sustained from etched Hal nanocomposites (up to ≈87% for 12 h) than from pristine Hal (up to ≈97% for 12 h) due to more intensive chitosan binding. High human fibroblast survival rates upon exposure to pristine and etched Hal before and after chitosan functionalization (>90% in the concentration of 1000 μg/mL) confirmed that both lumen etching under mild conditions and polymer functionalization had no significant effect on cytocompatibility. Based on these findings, selective lumen etching in combination with polycation modification appears to be a promising approach for improvement of Hal nanotubes functionality by increasing payload, polymer binding capacity, and sustained release properties with no significant effect on their cytocompatibility.
PB  - Elsevier Ltd
T2  - Materials Science and Engineering C
T1  - Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release
VL  - 123
DO  - 10.1016/j.msec.2021.112029
ER  - 

@article{
author = "Jauković, Valentina and Krajišnik, Danina and Daković, Aleksandra and Damjanović, Ana and Krstić, Jugoslav and Stojanović, Jovica and Čalija, Bojan",
year = "2021",
abstract = "The functionality of halloysite (Hal) nanotubes as drug carriers can be improved by lumen enlargement and polymer modification. This study investigates the influence of selective acid etching on Hal functionalization with cationic biopolymer chitosan. Hal was subjected to lumen etching under mild conditions, loaded under vacuum with nonsteroidal antiinflammatory drug aceclofenac, and incubated in an acidic solution of chitosan. The functionality of pristine and etched Hal before and upon polymer functionalization was assessed by ζ-potential measurements, structural characterization (FT-IR, DSC and XRPD analysis), cell viability assay, drug loading and drug release studies. Acid etching increased specific surface area, pore volume and pore size of Hal, decreased ζ-potential and facilitated binding of the cationic polymer. XRPD and DSC analysis revealed crystalline structure of etched Hal. Successful chitosan binding and drug entrapment were further confirmed by FT-IR and DSC studies. XRPD showed surface polymer binding. DSC and FT-IR analyses confirmed the presence of the entrapped drug in its crystalline form. Drug loading was increased for ≈81% by selective lumen etching. Slight decrease of drug content occurred during chitosan functionalization due to aceclofenac diffusion in the polymer solution. The drug release was more sustained from etched Hal nanocomposites (up to ≈87% for 12 h) than from pristine Hal (up to ≈97% for 12 h) due to more intensive chitosan binding. High human fibroblast survival rates upon exposure to pristine and etched Hal before and after chitosan functionalization (>90% in the concentration of 1000 μg/mL) confirmed that both lumen etching under mild conditions and polymer functionalization had no significant effect on cytocompatibility. Based on these findings, selective lumen etching in combination with polycation modification appears to be a promising approach for improvement of Hal nanotubes functionality by increasing payload, polymer binding capacity, and sustained release properties with no significant effect on their cytocompatibility.",
publisher = "Elsevier Ltd",
journal = "Materials Science and Engineering C",
title = "Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release",
volume = "123",
doi = "10.1016/j.msec.2021.112029"
}

Jauković, V., Krajišnik, D., Daković, A., Damjanović, A., Krstić, J., Stojanović, J.,& Čalija, B.. (2021). Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release. in Materials Science and Engineering C
Elsevier Ltd., 123.
https://doi.org/10.1016/j.msec.2021.112029

Jauković V, Krajišnik D, Daković A, Damjanović A, Krstić J, Stojanović J, Čalija B. Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release. in Materials Science and Engineering C. 2021;123.
doi:10.1016/j.msec.2021.112029 .

Jauković, Valentina, Krajišnik, Danina, Daković, Aleksandra, Damjanović, Ana, Krstić, Jugoslav, Stojanović, Jovica, Čalija, Bojan, "Influence of selective acid-etching on functionality of halloysite-chitosan nanocontainers for sustained drug release" in Materials Science and Engineering C, 123 (2021),
https://doi.org/10.1016/j.msec.2021.112029 . .

TY  - JOUR
AU  - Spasojević, Milica
AU  - Daković, Aleksandra
AU  - Rottinghaus, George E.
AU  - Obradović, Milena
AU  - Krajišnik, Danina
AU  - Marković, Marija
AU  - Krstić, Jugoslav
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3795
AB  - A natural kaolin from Serbia was modified with different amounts of octadecyldimethylbenzyl ammonium (ODMBA) - (25, 50 and 90% of kaolin cation exchange capacity). Samples were denoted as OKR-25, OKR-50 and OKR-90. Several methods (FTIR spectroscopy, thermal analysis, zeta potential measurements, and N2 physisorption) were used for characterization of the organokaolinites. Adsorption of the common mycotoxins - ochratoxin A (OCHRA) and zearalenone (ZEN) by the organokaolinites was investigated at different levels of solid phase in suspension, different initial mycotoxin concentrations and different pH values. The natural kaolin was not effective in binding OCHRA or ZEN. Adsorption of both mycotoxins by organokaolinites increased with increasing amounts of solid phase as well as with increasing levels of surfactant on the kaolin surface. OCHRA and ZEN adsorption by all organokaolinites followed non-linear adsorption isotherms, at pH 3, 7 and 9. The maximum adsorption capacity for OCHRA adsorption was at pH 3 (4.8 mg/g for OKR-25, 26.7 mg/g for OKR-50 and 39.2 mg/g for OKR-90) that was calculated from the Langmuir model. Much lower OCHRA adsorption capacities were found at pH 7 and 9 (from 0.8 mg/g to 6.9 mg/g at pH 7 and from 1.1 mg/g to 4.6 mg/g at pH 9). The following adsorption capacities for ZEN were obtained from the Langmuir isotherms, at pH 3: 4.5 mg/g for OKR-25, 12.0 mg/g for OKR-50 and 13.5 mg/g for OKR-90. At pH 7, adsorption of ZEN was 5.7 mg/g for OKR-25, 15.3 mg/g for OKR-90 and 14. 4 mg/g for OKR-90. At pH 9, ZEN adsorption capacities were 2.4, 14.1 and 8.1 mg/g for OKR-25, OKR-50 and OKR-90, respectively. Thus, at the lowest amount of ODMBA at the kaolin surface, adsorption of ZEN was similar at pH 3 and 7, while a slightly lower value was obtained for its adsorption at pH 9. With increasing amounts of organic phase at the kaolin surface, the adsorption of ZEN was practically independent of pH. Adsorption of both mycotoxins was dependent on the amount of ODMBA ions at the kaolin surface as well as on their forms in solution.
PB  - Elsevier Ltd
T2  - Applied Clay Science
T1  - Influence of surface coverage of kaolin with surfactant ions on adsorption of ochratoxin A and zearalenone
VL  - 205
DO  - 10.1016/j.clay.2021.106040
ER  - 

@article{
author = "Spasojević, Milica and Daković, Aleksandra and Rottinghaus, George E. and Obradović, Milena and Krajišnik, Danina and Marković, Marija and Krstić, Jugoslav",
year = "2021",
abstract = "A natural kaolin from Serbia was modified with different amounts of octadecyldimethylbenzyl ammonium (ODMBA) - (25, 50 and 90% of kaolin cation exchange capacity). Samples were denoted as OKR-25, OKR-50 and OKR-90. Several methods (FTIR spectroscopy, thermal analysis, zeta potential measurements, and N2 physisorption) were used for characterization of the organokaolinites. Adsorption of the common mycotoxins - ochratoxin A (OCHRA) and zearalenone (ZEN) by the organokaolinites was investigated at different levels of solid phase in suspension, different initial mycotoxin concentrations and different pH values. The natural kaolin was not effective in binding OCHRA or ZEN. Adsorption of both mycotoxins by organokaolinites increased with increasing amounts of solid phase as well as with increasing levels of surfactant on the kaolin surface. OCHRA and ZEN adsorption by all organokaolinites followed non-linear adsorption isotherms, at pH 3, 7 and 9. The maximum adsorption capacity for OCHRA adsorption was at pH 3 (4.8 mg/g for OKR-25, 26.7 mg/g for OKR-50 and 39.2 mg/g for OKR-90) that was calculated from the Langmuir model. Much lower OCHRA adsorption capacities were found at pH 7 and 9 (from 0.8 mg/g to 6.9 mg/g at pH 7 and from 1.1 mg/g to 4.6 mg/g at pH 9). The following adsorption capacities for ZEN were obtained from the Langmuir isotherms, at pH 3: 4.5 mg/g for OKR-25, 12.0 mg/g for OKR-50 and 13.5 mg/g for OKR-90. At pH 7, adsorption of ZEN was 5.7 mg/g for OKR-25, 15.3 mg/g for OKR-90 and 14. 4 mg/g for OKR-90. At pH 9, ZEN adsorption capacities were 2.4, 14.1 and 8.1 mg/g for OKR-25, OKR-50 and OKR-90, respectively. Thus, at the lowest amount of ODMBA at the kaolin surface, adsorption of ZEN was similar at pH 3 and 7, while a slightly lower value was obtained for its adsorption at pH 9. With increasing amounts of organic phase at the kaolin surface, the adsorption of ZEN was practically independent of pH. Adsorption of both mycotoxins was dependent on the amount of ODMBA ions at the kaolin surface as well as on their forms in solution.",
publisher = "Elsevier Ltd",
journal = "Applied Clay Science",
title = "Influence of surface coverage of kaolin with surfactant ions on adsorption of ochratoxin A and zearalenone",
volume = "205",
doi = "10.1016/j.clay.2021.106040"
}

Spasojević, M., Daković, A., Rottinghaus, G. E., Obradović, M., Krajišnik, D., Marković, M.,& Krstić, J.. (2021). Influence of surface coverage of kaolin with surfactant ions on adsorption of ochratoxin A and zearalenone. in Applied Clay Science
Elsevier Ltd., 205.
https://doi.org/10.1016/j.clay.2021.106040

Spasojević M, Daković A, Rottinghaus GE, Obradović M, Krajišnik D, Marković M, Krstić J. Influence of surface coverage of kaolin with surfactant ions on adsorption of ochratoxin A and zearalenone. in Applied Clay Science. 2021;205.
doi:10.1016/j.clay.2021.106040 .

Spasojević, Milica, Daković, Aleksandra, Rottinghaus, George E., Obradović, Milena, Krajišnik, Danina, Marković, Marija, Krstić, Jugoslav, "Influence of surface coverage of kaolin with surfactant ions on adsorption of ochratoxin A and zearalenone" in Applied Clay Science, 205 (2021),
https://doi.org/10.1016/j.clay.2021.106040 . .