Slobodan Gadžurić - Academia.edu (original) (raw)

Papers by Slobodan Gadžurić

The Journal of Physical Chemistry B

RSC Advances

Evolution of physicochemical parameters such as thermal stability, density, viscosity and electri... more Evolution of physicochemical parameters such as thermal stability, density, viscosity and electrical conductivity at various temperatures for two pharmaceutically active ionic liquids – tetracainium salicylate and tetracainium ibuprofenate.

Applied Radiation and Isotopes, 2021

Possible application of a novel ionic liquid 3-methylpiridinium salicylate (3-MPS) in Liquid Scin... more Possible application of a novel ionic liquid 3-methylpiridinium salicylate (3-MPS) in Liquid Scintillation Counting measurements has been explored. Its addition to several radionuclides' aqueous solutions shown a significant influence on 210Pb Cherenkov spectra, 210Pb and 226Ra gross alpha/beta spectra, even on 3H spectra appearance. 3-MPS manifested both wavelength shifting and scintillating effect, indicating that 3-MPS or other ionic liquids of similar structure soon might be implemented into the common LSC practise as an alternative to the commercial LSC cocktails.

Pharmaceutics, 2021

Ambroxol hydrochloride (AMB), used as a broncho secretolytic and an expectorant drug, is a semi-s... more Ambroxol hydrochloride (AMB), used as a broncho secretolytic and an expectorant drug, is a semi-synthetic derivative of vasicine obtained from the Indian shrub Adhatoda vasica. It is a metabolic product of bromhexine. The paper provides comprehensive and detailed research on ambroxol hydrochloride, gives information on thermal stability, the mechanism of AMB degradation, and data of practical interest for optimization of formulation that contains AMB as an active compound. Investigation on pure AMB and in commercial formulation Flavamed® tablet (FT), which contains AMB as an active compound, was performed systematically using thermal and spectroscopic methods, along with a sophisticated and practical statistical approach. AMB proved to be a heat-stable and humidity-sensitive drug. For its successful formulation, special attention should be addressed to excipients since it was found that polyvinyl pyrrolidone and Mg stearate affect the thermal stability of AMB. At the same time, lact...

Journal of Molecular Liquids, 2021

Abstract In this study, the influence of the structural modifications of 10 surface active ionic ... more Abstract In this study, the influence of the structural modifications of 10 surface active ionic liquids (SAILs), on toxicity towards wheat and barley germination and early growth was examined. First, SAILs containing 1,3-dialkylimiadzolium cation (1-dodecyl-3-methylimidazolium bromide, 1-dodecyl-3-ethylimidazolium bromide and 1-butyl-3-dodecylimidazolium bromide) were studied, followed by the study of SAILs containing methyl-pyridinium cation with the different position of the methyl group on pyridinium ring (N-dodecyl-2-methylpyridinium bromide, N-dodecyl-3-methylpyridinium bromide and N-dodecyl-4-methylpyridinium bromide). Furthermore, for the 1-dodecyl-3-methylimidazolium cation, the anion was changed from bromide to benzoate and hydroxybenzoate anions and the –OH group position on benzoate ring was varied (1-dodecyl-3-methylimidazolium benzoate, 1-dodecyl-3-methylimidazolium ortho-hydroxybenzoate, 1-dodecyl-3-methylimidazolium meta-hydroxybenzoate, 1-dodecyl-3-methylimidazolium para-hydroxybenzoate). The results showed that germination of both wheat and barley was decreased intensively with the increase in SAILs concentration. Moreover, the results demonstrated that the length of the longer alkyl substituent on the cation head has the most important role in toxicity, while change of the cation ring as well as the change in anion structure of the studied SAILs did not show a significant influence on germination of wheat and barley seeds and biomass reduction of young plants.

European Journal of Pharmaceutical Sciences, 2021

The present work focuses on modifying a local anaesthetic drug procaine into an ionic liquid and ... more The present work focuses on modifying a local anaesthetic drug procaine into an ionic liquid and evaluating the resulting thermal behaviour and structural changes. Counter ions, salicylate, ibuprofenate, and docusate, were chosen due to different hydrogen-bonding abilities, molecular size, charge distribution, and functional groups. After synthesis of procaine salicylate, procaine ibuprofenate, and procaine docusate, spectroscopic investigations were performed using infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy to confirm proton transfer. Differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis were used to determine the obtained ionic liquids' thermal behaviour. Experimental measurements of density, viscosity, and electrical conductivity were performed to get insight into the interactions occurring in the obtained ionic liquids. The viscosity and electrical conductivity data were analysed using the Vogel-Fulcher-Tammann (VFT) equation, while thermal expansion coefficients were calculated from measured density data. The obtained results found that the synthesised procaine salicylate and procaine docusate an ionic liquid's behaviours, including weak intermolecular forces, while procaine ibuprofenate showed more liquid co-crystal behaviour due to the absence of proton transfer for ibuprofen. In a theoretical phase of the investigation, the density functional theory (DFT) and molecular dynamics (MD) calculations were conducted. The obtained descriptors and radial distribution functions were used to analyse the interactions between ions of synthesised ionic liquids. In addition, solubility determination results proved that procaine transformation into procaine salicylate and procaine ibuprofenate ionic liquids enhanced its solubility in water, while procaine docusate reduces procaine solubility.

Journal of Molecular Liquids, 2020

Abstract In this work the influence of benzoate, ortho-, meta- and para-hydroxybenzoate anions, a... more Abstract In this work the influence of benzoate, ortho-, meta- and para-hydroxybenzoate anions, as counterions, on micellization process of 1-dodecyl-3-methyl-imidazolium cation in water is investigated by isothermal titration calorimetry (ITC) in the temeprature range between 278.15 and 318.15 K. ITC experimental data were analyzed by the help of an improved mass-action model, yielding the values of critical micelle concentration, cmc, the degree of counterion binding, β, aggregation number, n, standard heat capacity, ΔMcpθ, enthalpy, ∆MHθ, entropy, ∆MSθ, and Gibbs free energy, ∆MGθ of micellization. It was found that the investigated systems behave mainly like common ionic surfactants and already investigated SAILs: the micellization process of investigated systems is entropically driven at low temperatures, whereas at high temperatures the enthalpic contribution becomes equally important. The last is especially important in the case of ortho-hydroxybenzoate, which incorporates into micellar structure affecting also the entropy-enthalpy compensation. But evidently, the presence and position of –OH group in the counterion influence considerably the micellization process. ΔMcpθ values were further discussed in the light of the removal of water molecules from contact with nonpolar surface area upon micelle formation. All the values are negative, the most in the case of benzoate anion, which could be ascribed to the absence of –OH group. To refine the thermodynamic parameters obtained from ITC, the molecular simulations were performed. First, it is shown that the binding energies between anion and cations increase in the order from benzoate to para-, meta- and ortho-hydroxybenzoate, which coincide with ∆MHθ values. Second, it is demonstrated that water around counterions is strongly perturbed leading to differences in ΔMcpθ.