N. Galić - Academia.edu (original) (raw)
Papers by N. Galić
Molecular Pharmaceutics
Praziquantel (PZQ) is a biopharmaceutical classification system (BCS) class II anthelmintic drug ... more Praziquantel (PZQ) is a biopharmaceutical classification system (BCS) class II anthelmintic drug characterized by poor solubility and a bitter taste, both of which can be addressed by inclusion complexation with cyclodextrins (CD). In this work, a comprehensive investigation of praziquantel/cyclodextrin (PZQ/CD) complexes was conducted by means of UV−vis spectroscopy, spectrofluorimetry, NMR spectroscopy, liquid chromatography-high-resolution mass spectrometry (LC-HRMS/MS), and molecular modeling. Phase solubility studies revealed that among four CDs tested, the randomly methylated β-CD (RMβCD) and the sulfobutylether sodium salt β-CD (SBEβCD) resulted in the highest increase in PZQ solubility (approximately 16-fold). The formation of 1:1 inclusion complexes was confirmed by HRMS, NMR, and molecular modeling. Both cyclohexane and the central pyrazino ring, as well as an aromatic part of PZQ are included in the CD central cavity through several different binding modes, which exist simultaneously. Furthermore, the influence of CDs on PZQ stability was investigated in solution (HCl, NaOH, H 2 O 2) and in the solid state (accelerated degradation, photostability) by ultra-high-performance liquid chromatography−diode array detection−tandem mass spectrometry (UPLC-DAD/MS). CD complexation promoted new degradation pathways of the drug. In addition to three already known PZQ degradants, seven new degradation products were identified (m/z 148, 215, 217, 301, 327, 343, and 378) and their structures were proposed based on HRMS/MS data. Solid complexes were prepared by mechanochemical activation, a solvent-free and ecologically acceptable method.
Archives of Industrial Hygiene and Toxicology
Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means ... more Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means that while one is active, the other can be inactive or even harmful. Due to their high consumption and incomplete degradation in waste water, they may reach surface waters and affect aquatic organisms. To address this issue we developed a chromatographic method suitable for determining beta-blocker enantiomers in surface waters. It was tested on five beta-blockers (acebutolol, atenolol, bisoprolol, labetalol and metoprolol) and validated on bisoprolol enantiomers. Good enantioseparation of all analysed beta-blockers was achieved on the Chirobiotic V column with the mobile phase composed of methanol/acetic acid/triethylamine (100/0.20/0.15 v/v/v) at a flow rate of 0.5 mL/min and column temperature of 45 °C. Method proved to be linear in the concentration range from 0.075 µg/mL to 5 µg/mL, and showed good recovery. The limits of bisoprolol enantiomer detection were 0.025 µg/mL and 0.026 µg...
Applied Sciences
In this study, the preservation of As(III) in model solutions and natural groundwater samples fro... more In this study, the preservation of As(III) in model solutions and natural groundwater samples from four locations in Croatia was conducted. Model laboratory samples were spiked with As(III) and As(V), and different complexing agents. Solutions were analysed in intervals of 24, 48 h and during ten days after preparation. Model samples containing citric acid, sodium citrate, sodium oxalate and potassium sodium tartrate in combination with acetic acid, spiked with As(III)and As(V), showed good species preservation. As(III), in model samples, was preserved for 7 days with citric acid, and citric acid in combination with acetic acid, as well as with tartrate. As(III), in natural samples, was preserved for 6 to 12 days with potassium sodium tartrate, citric acid, and citric acid in combination with acetic acid and showed improvement, compared with unpreserved samples (oxidation in 3 days). The results showed that acetic acid alone was not successful in preserving As speciation. Good resol...
Journal of Molecular Structure
Analytical Methods
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for quantification of... more A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for quantification of four potential genotoxic impurities (PGIs) in the ceritinib active pharmaceutical ingredient.
Journal of Molecular Structure
Journal of Liquid Chromatography & Related Technologies
![Research paper thumbnail of UV-Vis and ESI MS/MS Study of Calix[4]arene Derivatives and Their Lanthanide Complexes](https://attachments.academia-assets.com/69972198/thumbnails/1.jpg)
](Croatica Chemica Acta
Coordination properties of calix[4]arenes bearing substituents on the lower rim: tetraethyl ester... more Coordination properties of calix[4]arenes bearing substituents on the lower rim: tetraethyl ester (1), tetraethylamide (2), and newly synthesized tetraethylmethylamide derivative (3), towards selected lanthanide cations (La 3+ , Eu 3+ , Yb 3+) were studied by spectrophotometric titrations. No complexation was observed with ester derivative, while amide derivatives formed 1:1 complexes and bound lanthanide cations very efficiently (lgKLa2 = 5.1; lgKEu2 ≥ 6; lgKYb2 ≥ 6; lgKLa3 ≥ 6; lgKEu3 ≥ 6; lgKYb3 ≥ 6). The ligands and complexes were also analysed by ESI MS and MS/MS spectrometry. Both inductive cleavage and proton rearrangement fragmentation reactions were observed. Corresponding fragmentation pathways were proposed. The results obtained by MS analysis were in accordance with those obtained by spectrophotometric titrations.
Biotechnology & Biotechnological Equipment
Hydrazones have versatile properties that make them promising for a range of possible application... more Hydrazones have versatile properties that make them promising for a range of possible applications. In this study, we examined a library of 17 aroylhydrazones derived from nicotinic acid hydrazide (1-12) and isonicotinic acid hydrazide (A-E) created by us for their biological activity. The antiproliferative activity of the compounds was investigated on non-tumour MCF-10A cells and cancer cell lines, MCF-7 and MDA-MB-231. Four compounds were selected as most active in cell growth inhibition of the tumour cell lines. These compounds, 5, 11, C and E, were tested on four additional cell lines: non-tumour BJ and cancer cell lines, HeLa, HepG2 and HT-29. Compounds 5 and E exhibited the highest selectivity index on cancer cell lines MDA-MB-231, HeLa and HepG2. High selectivity to MCF-7 cells was demonstrated with compound 5. Compound C was very selective to HepG2 cells as well as to MDA-MB-231 but to a lesser degree. Compound 11 showed selectivity against MDA-MB-231. The obtained results allow assessing the structure-activity relationship of the compounds and provide insight into the further development of this group of aroylhydrazones as more potent and selective anti-neoplastic agents.
Acta Pharmaceutica
Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′-(2-h... more Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′-(2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide (2), N′-(5-chloro-2-hydroxyphenyl-methylidene)-3-pyridinecarbohydrazide (10), N′-(3,5-chloro-2-hydroxyphenylmethylidene)-3-pyridinecarbohydrazide (11), and N′-(2-hydroxy-5-nitrophenylmethylidene)-3-pyridinecarbohydrazide (12) showed antibacterial activity against Escherichia coli, with MIC values (in µmol mL−1) of 0.18–0.23, 0.11–0.20, 0.16–0.17 and 0.35–0.37, resp. Compounds 11 and 12, as well as N′-(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (6) and N′-(2-hydroxy-5- methoxyphenylmethylidene)-3-pyridinecarbohydrazide (8) showed antibacterial activity against Staphylococcus aureus, with the lowest MIC values of 0.005–0.2, 0.05–0.12, 0.06–0.48 and 0.17–0.99 µmol mL−1. N′-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (7) showed antifungal activity against both fluconazole resistant and susceptible C. a...
Croatica Chemica Acta
Small scale experimental model for the preparation of methyl ester of etodolac, the key intermedi... more Small scale experimental model for the preparation of methyl ester of etodolac, the key intermediate in the synthesis of nonsteroidal drug etodolac, is thoroughly investigated in order to define the key parameters needed for its large scale production. Oxa-Pictet-Spengler reaction of 7-ethyltryptophol and methyl 3-oxopentanoate with inorganic acids as catalysts was monitored over time using HPLC method with UV detection. HPLC method for the simultaneous determination of 7-ethyltryptophol and the product was developed first. The conversion of 7-ethyltryptophol to etodolac precursor was performed using different molar equivalents of acid (1-5 with respect to the β-ketoester) and starting 7-ethyltryptophol of different degrees of purity. Kinetic profiles and optimal reaction times were in each case defined and key parameters selected.
Environmental Science and Pollution Research
Sulfonamides, macrolides, torasemide, fumagillin, and chloramphenicol were simultaneously analyze... more Sulfonamides, macrolides, torasemide, fumagillin, and chloramphenicol were simultaneously analyzed in surface water samples by using solid-phase extraction (SPE) and reversed-phase (RP) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS). In the pre-concentration and clean-up process, the pH value of samples and volume of the solvent for extraction of analytes from cartridge were optimized. Extraction recoveries were high with values in the range from 62 to 115%. Limits of quantification (LoQ) were in the range from 0.02 to 0.2 μg L-1. Repeatability of the method was evaluated at LoQ and expressed as relative standard deviation (RSD). Calculated RSDs were low with values in the range from 2.4 to 14.5%. The method was successfully applied for analysis of surface water real samples. Samples were collected along the rivers in Croatia on four sampling sites in 2012 in Danube catchment areas, 19 sampling sites in Danube and Adriatic catchment areas in 2013, and another 19 places in 2014. Altogether, 20 target compounds were analyzed in 148 water samples and detected in 31 samples in range (0.1-5.3) μg L-1 or in 20.1% of samples. The most frequent and highest concentrations were detected for macrolide antibiotics. This is the first attempt of such monitoring in surface waters in Croatia.
Journal of pharmaceutical and biomedical analysis, Jan 15, 2017
Mechanochemical activation using several different co-grinding additives was applied as a green c... more Mechanochemical activation using several different co-grinding additives was applied as a green chemistry approach to improve physiochemical and biopharmaceutical properties of praziquantel (PZQ). Liquid assisted grinding with an equimolar amount of citric acid (CA), malic acid (MA), salicylic acid (SA) and tartaric acid (TA) gained in cocrystal formation, which all showed pH-dependent solubility and dissolution rate. However, the most soluble cocrystal of PZQ with MA was chemically unstable, as seen during the stability testing. Equimolar cyclodextrin complexes prepared by neat grinding with amorphous hydroxypropyl-β-cyclodextrin (HPβCD) and randomly methylated β-cyclodextrin (MEβCD) showed the highest improvement in drug solubility and the dissolution rate, but only PZQ/HPβCD product presented an acceptable chemical and photostability profile. A combined approach, by co-grinding the drug with both MA and HPβCD in equimolar ratio, also gave highly soluble amorphous product which ag...
![Research paper thumbnail of Extraction and complexation of alkali and alkaline earth metal cations by lower-rim calix[4]arene diethylene glycol amide derivatives](https://attachments.academia-assets.com/69972227/thumbnails/1.jpg)
](New J. Chem., 2015
The metal-ion extraction abilities of calix[4]arene derivatives 1 and 2 are largely dependent on ... more The metal-ion extraction abilities of calix[4]arene derivatives 1 and 2 are largely dependent on the type of the amide group forming the cation-binding site. Tertiary-amide derivative 2 was shown to be an excellent extractant for most alkali and alkaline earth cations.
Food Hydrocolloids, 2015
ABSTRACT The aim of the study is to prepare and characterize gelatin films incorporating hemp and... more ABSTRACT The aim of the study is to prepare and characterize gelatin films incorporating hemp and sage oil, to obtain an edible film which combines both food preservation and nutritional properties. Gelatin film-forming solutions were investigated in terms of wettability in relation to different foodstuff and their antimicrobial properties against Escherichia coli, Staphylococcus aureus, Listeria innocua, Saccharomyces cerevisiae and Penicillium expansum. The gelatin films were evaluated for their water vapor permeability, solubility in food simulants, moisture content, thickness and light barrier property. The steeper decrease in contact angles, surface tension and spreading coefficients was displayed by the sage oil-gelatin film solution and the mildest by the hemp oil-gelatin film solution. The most suitable foodstuffs to be coated in sage/hemp oil-gelatin films seem to be Golden Apple, pork meat and processed cheese, whereas the least suitable appear to be garlic, red bell pepper and cauliflower. Hemp oil has moderate antimicrobial action, while the sage oil displays a strong inhibition. Additive effect is expressed in case of all gelatin film solutions containing sage and hemp oils combinations. The sage oil-gelatin film displays the lowest water vapor permeability and moisture content, while the hemp oil-gelatin film results in the lowest thickness and highest light barrier property. Hemp oil-gelatin film is more soluble than the sage oil-gelatin film. Varying degrees in the investigated parameters can be noticed in cases of oils mixtures-gelatin films depending by the dominant oil.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 15, 2008
Electronic absorption and emission properties of a series of Schiff bases derived from 2-hydroxy-... more Electronic absorption and emission properties of a series of Schiff bases derived from 2-hydroxy-3-methoxybenzaldehyde and 2-aminopyridine, 2,3-diaminopyridine, 2,6-diaminopyridine, or 3-aminomethylpyridine were studied in solvents of different polarities. The interconversion of the enolimine to the ketoamine tautomeric form was observed for compound 1, 6-methoxy-2-(3-pyridylmethyliminomethyl)phenol, and the corresponding equilibrium constant was estimated in several solvents. Protonation constants of all the investigated compounds were determined spectrophotometrically in the methanol/water 1/4 system. The effect of copper(II) ions on absorption and on the emission spectra of these ligands was examined in the buffered dioxane/water 1/1 system (pH 5.8). Strong complexation of Cu(II) and formation of a 1:1 complex were observed for the bis-Schiff base derived from 2,3-diaminopyridine. The complex of copper(II) with compound 1 was isolated and characterized by elemental analysis, magn...
Toxicology Letters, 2012
Human exposure to atrazine and other triazine herbicides results in urinary excretion of traces o... more Human exposure to atrazine and other triazine herbicides results in urinary excretion of traces of parent compounds and of their metabolites formed by N-dealkylation or conjugation with mercapturic acid. In contrast to N-dealkylated metabolites, which are not compound-specific, the measurement of atrazine mercapturate and unchanged atrazine provides an unambiguous confirmation of exposure to this herbicide. The aim of this study was to investigate the levels of these two compounds in a group of agricultural workers who may be considered representative for typical behaviour and procedures during the atrazine application in Croatia. The spot urine samples were collected at the beginning (samples A) and at the end (samples B) of a working day and 12 h after exposure has ended (samples C). Atrazine and atrazine mercapturate were extracted from acidified urine samples (pH 2) with ethyl acetate and the extracts were analysed using high performance liquid chromatography-tandem mass spectrometry with a turbo ion spray (electrospray) ionization interface. The detection limits based on treatment of 2 ml urine samples were 0.2 ng ml −1 for both analytes. Atrazine was not detected in any of 27 analysed urine samples but traces of atrazine mercapturate were measured in about a third of pre-exposure and in all post-exposure urine samples in mass concentrations ranging from 0.3 to 10.4 ng ml −1 (0.3 to 8.0 g g −1 of creatinine). The metabolite concentrations in B and C group of post-exposure samples were not significantly different. The urinary atrazine mercapturate post-exposure concentrations were comparable to those reported for U.S. farmers engaged in a single field application of atrazine.
![Research paper thumbnail of Fluorescent Phenanthridine-Based Calix[4]arene Derivatives: Synthesis and Thermodynamic and Computational Studies of their Complexation with Alkali-Metal Cations](https://attachments.academia-assets.com/69972228/thumbnails/1.jpg)
](RSC Adv., 2015
The novel calix[4]arenes exhibiting prominent fluorescence were shown to be potential sensitive f... more The novel calix[4]arenes exhibiting prominent fluorescence were shown to be potential sensitive fluorimetric cation sensors. Comprehensive experimental and computational studies provided detailed insight into the corresponding complexation reactions.
Molecular Pharmaceutics
Praziquantel (PZQ) is a biopharmaceutical classification system (BCS) class II anthelmintic drug ... more Praziquantel (PZQ) is a biopharmaceutical classification system (BCS) class II anthelmintic drug characterized by poor solubility and a bitter taste, both of which can be addressed by inclusion complexation with cyclodextrins (CD). In this work, a comprehensive investigation of praziquantel/cyclodextrin (PZQ/CD) complexes was conducted by means of UV−vis spectroscopy, spectrofluorimetry, NMR spectroscopy, liquid chromatography-high-resolution mass spectrometry (LC-HRMS/MS), and molecular modeling. Phase solubility studies revealed that among four CDs tested, the randomly methylated β-CD (RMβCD) and the sulfobutylether sodium salt β-CD (SBEβCD) resulted in the highest increase in PZQ solubility (approximately 16-fold). The formation of 1:1 inclusion complexes was confirmed by HRMS, NMR, and molecular modeling. Both cyclohexane and the central pyrazino ring, as well as an aromatic part of PZQ are included in the CD central cavity through several different binding modes, which exist simultaneously. Furthermore, the influence of CDs on PZQ stability was investigated in solution (HCl, NaOH, H 2 O 2) and in the solid state (accelerated degradation, photostability) by ultra-high-performance liquid chromatography−diode array detection−tandem mass spectrometry (UPLC-DAD/MS). CD complexation promoted new degradation pathways of the drug. In addition to three already known PZQ degradants, seven new degradation products were identified (m/z 148, 215, 217, 301, 327, 343, and 378) and their structures were proposed based on HRMS/MS data. Solid complexes were prepared by mechanochemical activation, a solvent-free and ecologically acceptable method.
Archives of Industrial Hygiene and Toxicology
Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means ... more Beta-blockers are chiral compounds with enantiomers that have different bioactivity, which means that while one is active, the other can be inactive or even harmful. Due to their high consumption and incomplete degradation in waste water, they may reach surface waters and affect aquatic organisms. To address this issue we developed a chromatographic method suitable for determining beta-blocker enantiomers in surface waters. It was tested on five beta-blockers (acebutolol, atenolol, bisoprolol, labetalol and metoprolol) and validated on bisoprolol enantiomers. Good enantioseparation of all analysed beta-blockers was achieved on the Chirobiotic V column with the mobile phase composed of methanol/acetic acid/triethylamine (100/0.20/0.15 v/v/v) at a flow rate of 0.5 mL/min and column temperature of 45 °C. Method proved to be linear in the concentration range from 0.075 µg/mL to 5 µg/mL, and showed good recovery. The limits of bisoprolol enantiomer detection were 0.025 µg/mL and 0.026 µg...
Applied Sciences
In this study, the preservation of As(III) in model solutions and natural groundwater samples fro... more In this study, the preservation of As(III) in model solutions and natural groundwater samples from four locations in Croatia was conducted. Model laboratory samples were spiked with As(III) and As(V), and different complexing agents. Solutions were analysed in intervals of 24, 48 h and during ten days after preparation. Model samples containing citric acid, sodium citrate, sodium oxalate and potassium sodium tartrate in combination with acetic acid, spiked with As(III)and As(V), showed good species preservation. As(III), in model samples, was preserved for 7 days with citric acid, and citric acid in combination with acetic acid, as well as with tartrate. As(III), in natural samples, was preserved for 6 to 12 days with potassium sodium tartrate, citric acid, and citric acid in combination with acetic acid and showed improvement, compared with unpreserved samples (oxidation in 3 days). The results showed that acetic acid alone was not successful in preserving As speciation. Good resol...
Journal of Molecular Structure
Analytical Methods
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for quantification of... more A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used for quantification of four potential genotoxic impurities (PGIs) in the ceritinib active pharmaceutical ingredient.
Journal of Molecular Structure
Journal of Liquid Chromatography & Related Technologies
Croatica Chemica Acta
Coordination properties of calix[4]arenes bearing substituents on the lower rim: tetraethyl ester... more Coordination properties of calix[4]arenes bearing substituents on the lower rim: tetraethyl ester (1), tetraethylamide (2), and newly synthesized tetraethylmethylamide derivative (3), towards selected lanthanide cations (La 3+ , Eu 3+ , Yb 3+) were studied by spectrophotometric titrations. No complexation was observed with ester derivative, while amide derivatives formed 1:1 complexes and bound lanthanide cations very efficiently (lgKLa2 = 5.1; lgKEu2 ≥ 6; lgKYb2 ≥ 6; lgKLa3 ≥ 6; lgKEu3 ≥ 6; lgKYb3 ≥ 6). The ligands and complexes were also analysed by ESI MS and MS/MS spectrometry. Both inductive cleavage and proton rearrangement fragmentation reactions were observed. Corresponding fragmentation pathways were proposed. The results obtained by MS analysis were in accordance with those obtained by spectrophotometric titrations.
Biotechnology & Biotechnological Equipment
Hydrazones have versatile properties that make them promising for a range of possible application... more Hydrazones have versatile properties that make them promising for a range of possible applications. In this study, we examined a library of 17 aroylhydrazones derived from nicotinic acid hydrazide (1-12) and isonicotinic acid hydrazide (A-E) created by us for their biological activity. The antiproliferative activity of the compounds was investigated on non-tumour MCF-10A cells and cancer cell lines, MCF-7 and MDA-MB-231. Four compounds were selected as most active in cell growth inhibition of the tumour cell lines. These compounds, 5, 11, C and E, were tested on four additional cell lines: non-tumour BJ and cancer cell lines, HeLa, HepG2 and HT-29. Compounds 5 and E exhibited the highest selectivity index on cancer cell lines MDA-MB-231, HeLa and HepG2. High selectivity to MCF-7 cells was demonstrated with compound 5. Compound C was very selective to HepG2 cells as well as to MDA-MB-231 but to a lesser degree. Compound 11 showed selectivity against MDA-MB-231. The obtained results allow assessing the structure-activity relationship of the compounds and provide insight into the further development of this group of aroylhydrazones as more potent and selective anti-neoplastic agents.
Acta Pharmaceutica
Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′-(2-h... more Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′-(2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide (2), N′-(5-chloro-2-hydroxyphenyl-methylidene)-3-pyridinecarbohydrazide (10), N′-(3,5-chloro-2-hydroxyphenylmethylidene)-3-pyridinecarbohydrazide (11), and N′-(2-hydroxy-5-nitrophenylmethylidene)-3-pyridinecarbohydrazide (12) showed antibacterial activity against Escherichia coli, with MIC values (in µmol mL−1) of 0.18–0.23, 0.11–0.20, 0.16–0.17 and 0.35–0.37, resp. Compounds 11 and 12, as well as N′-(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (6) and N′-(2-hydroxy-5- methoxyphenylmethylidene)-3-pyridinecarbohydrazide (8) showed antibacterial activity against Staphylococcus aureus, with the lowest MIC values of 0.005–0.2, 0.05–0.12, 0.06–0.48 and 0.17–0.99 µmol mL−1. N′-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (7) showed antifungal activity against both fluconazole resistant and susceptible C. a...
Croatica Chemica Acta
Small scale experimental model for the preparation of methyl ester of etodolac, the key intermedi... more Small scale experimental model for the preparation of methyl ester of etodolac, the key intermediate in the synthesis of nonsteroidal drug etodolac, is thoroughly investigated in order to define the key parameters needed for its large scale production. Oxa-Pictet-Spengler reaction of 7-ethyltryptophol and methyl 3-oxopentanoate with inorganic acids as catalysts was monitored over time using HPLC method with UV detection. HPLC method for the simultaneous determination of 7-ethyltryptophol and the product was developed first. The conversion of 7-ethyltryptophol to etodolac precursor was performed using different molar equivalents of acid (1-5 with respect to the β-ketoester) and starting 7-ethyltryptophol of different degrees of purity. Kinetic profiles and optimal reaction times were in each case defined and key parameters selected.
Environmental Science and Pollution Research
Sulfonamides, macrolides, torasemide, fumagillin, and chloramphenicol were simultaneously analyze... more Sulfonamides, macrolides, torasemide, fumagillin, and chloramphenicol were simultaneously analyzed in surface water samples by using solid-phase extraction (SPE) and reversed-phase (RP) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS). In the pre-concentration and clean-up process, the pH value of samples and volume of the solvent for extraction of analytes from cartridge were optimized. Extraction recoveries were high with values in the range from 62 to 115%. Limits of quantification (LoQ) were in the range from 0.02 to 0.2 μg L-1. Repeatability of the method was evaluated at LoQ and expressed as relative standard deviation (RSD). Calculated RSDs were low with values in the range from 2.4 to 14.5%. The method was successfully applied for analysis of surface water real samples. Samples were collected along the rivers in Croatia on four sampling sites in 2012 in Danube catchment areas, 19 sampling sites in Danube and Adriatic catchment areas in 2013, and another 19 places in 2014. Altogether, 20 target compounds were analyzed in 148 water samples and detected in 31 samples in range (0.1-5.3) μg L-1 or in 20.1% of samples. The most frequent and highest concentrations were detected for macrolide antibiotics. This is the first attempt of such monitoring in surface waters in Croatia.
Journal of pharmaceutical and biomedical analysis, Jan 15, 2017
Mechanochemical activation using several different co-grinding additives was applied as a green c... more Mechanochemical activation using several different co-grinding additives was applied as a green chemistry approach to improve physiochemical and biopharmaceutical properties of praziquantel (PZQ). Liquid assisted grinding with an equimolar amount of citric acid (CA), malic acid (MA), salicylic acid (SA) and tartaric acid (TA) gained in cocrystal formation, which all showed pH-dependent solubility and dissolution rate. However, the most soluble cocrystal of PZQ with MA was chemically unstable, as seen during the stability testing. Equimolar cyclodextrin complexes prepared by neat grinding with amorphous hydroxypropyl-β-cyclodextrin (HPβCD) and randomly methylated β-cyclodextrin (MEβCD) showed the highest improvement in drug solubility and the dissolution rate, but only PZQ/HPβCD product presented an acceptable chemical and photostability profile. A combined approach, by co-grinding the drug with both MA and HPβCD in equimolar ratio, also gave highly soluble amorphous product which ag...
New J. Chem., 2015
The metal-ion extraction abilities of calix[4]arene derivatives 1 and 2 are largely dependent on ... more The metal-ion extraction abilities of calix[4]arene derivatives 1 and 2 are largely dependent on the type of the amide group forming the cation-binding site. Tertiary-amide derivative 2 was shown to be an excellent extractant for most alkali and alkaline earth cations.
Food Hydrocolloids, 2015
ABSTRACT The aim of the study is to prepare and characterize gelatin films incorporating hemp and... more ABSTRACT The aim of the study is to prepare and characterize gelatin films incorporating hemp and sage oil, to obtain an edible film which combines both food preservation and nutritional properties. Gelatin film-forming solutions were investigated in terms of wettability in relation to different foodstuff and their antimicrobial properties against Escherichia coli, Staphylococcus aureus, Listeria innocua, Saccharomyces cerevisiae and Penicillium expansum. The gelatin films were evaluated for their water vapor permeability, solubility in food simulants, moisture content, thickness and light barrier property. The steeper decrease in contact angles, surface tension and spreading coefficients was displayed by the sage oil-gelatin film solution and the mildest by the hemp oil-gelatin film solution. The most suitable foodstuffs to be coated in sage/hemp oil-gelatin films seem to be Golden Apple, pork meat and processed cheese, whereas the least suitable appear to be garlic, red bell pepper and cauliflower. Hemp oil has moderate antimicrobial action, while the sage oil displays a strong inhibition. Additive effect is expressed in case of all gelatin film solutions containing sage and hemp oils combinations. The sage oil-gelatin film displays the lowest water vapor permeability and moisture content, while the hemp oil-gelatin film results in the lowest thickness and highest light barrier property. Hemp oil-gelatin film is more soluble than the sage oil-gelatin film. Varying degrees in the investigated parameters can be noticed in cases of oils mixtures-gelatin films depending by the dominant oil.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 15, 2008
Electronic absorption and emission properties of a series of Schiff bases derived from 2-hydroxy-... more Electronic absorption and emission properties of a series of Schiff bases derived from 2-hydroxy-3-methoxybenzaldehyde and 2-aminopyridine, 2,3-diaminopyridine, 2,6-diaminopyridine, or 3-aminomethylpyridine were studied in solvents of different polarities. The interconversion of the enolimine to the ketoamine tautomeric form was observed for compound 1, 6-methoxy-2-(3-pyridylmethyliminomethyl)phenol, and the corresponding equilibrium constant was estimated in several solvents. Protonation constants of all the investigated compounds were determined spectrophotometrically in the methanol/water 1/4 system. The effect of copper(II) ions on absorption and on the emission spectra of these ligands was examined in the buffered dioxane/water 1/1 system (pH 5.8). Strong complexation of Cu(II) and formation of a 1:1 complex were observed for the bis-Schiff base derived from 2,3-diaminopyridine. The complex of copper(II) with compound 1 was isolated and characterized by elemental analysis, magn...
Toxicology Letters, 2012
Human exposure to atrazine and other triazine herbicides results in urinary excretion of traces o... more Human exposure to atrazine and other triazine herbicides results in urinary excretion of traces of parent compounds and of their metabolites formed by N-dealkylation or conjugation with mercapturic acid. In contrast to N-dealkylated metabolites, which are not compound-specific, the measurement of atrazine mercapturate and unchanged atrazine provides an unambiguous confirmation of exposure to this herbicide. The aim of this study was to investigate the levels of these two compounds in a group of agricultural workers who may be considered representative for typical behaviour and procedures during the atrazine application in Croatia. The spot urine samples were collected at the beginning (samples A) and at the end (samples B) of a working day and 12 h after exposure has ended (samples C). Atrazine and atrazine mercapturate were extracted from acidified urine samples (pH 2) with ethyl acetate and the extracts were analysed using high performance liquid chromatography-tandem mass spectrometry with a turbo ion spray (electrospray) ionization interface. The detection limits based on treatment of 2 ml urine samples were 0.2 ng ml −1 for both analytes. Atrazine was not detected in any of 27 analysed urine samples but traces of atrazine mercapturate were measured in about a third of pre-exposure and in all post-exposure urine samples in mass concentrations ranging from 0.3 to 10.4 ng ml −1 (0.3 to 8.0 g g −1 of creatinine). The metabolite concentrations in B and C group of post-exposure samples were not significantly different. The urinary atrazine mercapturate post-exposure concentrations were comparable to those reported for U.S. farmers engaged in a single field application of atrazine.
RSC Adv., 2015
The novel calix[4]arenes exhibiting prominent fluorescence were shown to be potential sensitive f... more The novel calix[4]arenes exhibiting prominent fluorescence were shown to be potential sensitive fluorimetric cation sensors. Comprehensive experimental and computational studies provided detailed insight into the corresponding complexation reactions.