Martina Periša

Photolytic degradation of norfloxacin, enrofloxacin and ciprofloxacin in various aqueous media

The photolytic degradation of norfloxacin, enrofloxacin and ciprofloxacin, fluoroquinolone antibacterials widely used in human and veterinary medicine, was investigated under simulated solar irradiation in different water matrices (river water and synthetic wastewater similar by composition to wastewater of pharmaceutical industry). The results showed that investigated fluoroquinolones degrade very quickly and photodegradation followed pseudo first order kinetics. The slowest photodegradation rate was observed in river water for all three fluoroquinolones. In the case of pharmaceutical mixture irradiation, no significant differences in rate constants were observed compared to single-component experiments. The structures of photodegradation products were determined and photodegradation pathways were suggested. Two main processes occurred primary from enrofloxacin depending on pH values: (I) cyclopropane ring cleavage at pH 4 and (II) oxidative photodegradation at pH 8. The structures of the photoproducts E-1 to E-6 are unknown and have not been reported for this fluoroquinolone. For ciprofloxacin two main processes were also identified depending on experimental conditions. Under acidic conditions (pH 4), reactions involved rather the quinolone ring (cleavage of the cyclopropane ring and fluorine solvolysis), while at pH 8 the side-chain reactions took place. The photodegradation pathway of norfloxacin somewhat differed from the previous two. There was no significant dependence on reaction conditions and there were no two different pathways. Determination and identification of photodegradation products were performed by liquid chromatography-mass spectrometry (LC-MS/MS). The obtained results are of importance for assessing the environmental fate of fluoroquinolones in aqueous media.

Optimization of matrix solid-phase dispersion for liquid chromatography tandem mass spectrometry analysis of 12 pharmaceuticals in sediments.

The matrix solid-phase dispersion (MSPD) technique accompanied with LC-MS/MS detection for the purpose of determination of 12 pharmaceuticals (sulfaguanidine, sulfadiazine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, praziquantel, febantel, enrofloxacin, ciprofloxacin, norfloxacin and procaine) applied to sediment samples has been described in this paper. Different parameters, such as the type of solid phase, the elution solvent and its volume have been investigated. The analytes were successfully extracted by C18 as an MSPD sorbent with 5 mL of acetonitrile:5% of oxalic acid=6:4 (v/v) as an elution solvent. The proposed method provides a linear response over the concentration range of 0.0005-100 μg/g, depending on pharmaceuticals with correlation coefficients above 0.9928 in all cases except for trimethoprim (0.9889). Also, the method has revealed low limits of detection (0.125-500 ng/g), good precision (intra and inter-day), a relative standard deviation below 15% and recoveries above 80%, except for roxithromycin, febantel and enrofloxacin. The method has been successfully applied to analysis of different sediment samples.

Simultaneous determination of pharmaceuticals and some of their metabolites in wastewaters by high performance liquid chromatography with tandem mass spectrometry

The present work describes the development of a sensitive and reliable analytical method based on solid-phase extraction followed by analysis using liquid chromatography with tandem mass spectrometry for the simultaneous determination of pharmaceuticals from antibiotics (fluoroquinolones, sulfonamides, and their N(4)-acetyl metabolites, and trimethoprim as sulfonamides synergist) and anthelmintics groups. SPE was optimized using different cartridges (Strata-X, Oasis HLB, Strata C18 -E, Isolute C18 , SampliQ C8 /Si-SCX). The highest recovery was achieved using Strata X cartridge (>80%) with good reproducibility (RSDs < 5%) despite various physicochemical properties of the compounds. Investigated analytes were identified and quantitatively determined by liquid chromatography with tandem mass spectrometry using multiple reaction monitoring. The method was shown to be linear over the concentration range of 0.05-30 μg/L for febantel and albendazole, and 0.10-60 μg/L for all other pharmaceuticals. Correlation coefficients were >0.99 for all compounds except for sulfamethazine (0.98). In order to demonstrate the applicability of the developed method, wastewater from the veterinary industry was analyzed. Results evidenced the presence of febantel, praziquantel, albendazole, enrofloxacin, sulfamethazine, and sulfadiazine.

NF/RO removal of enrofloxacin and its photodegradation products from water

Abstract Once released into the environment pharmaceuticals undergo a series of processes leading to their degradation. Photolysis induced by sunlight is the most important way of pharmaceuticals degradation in water. In this work the removal of enrofloxacin (ENRO) and its photodegradation products with nanofiltration (NF) and reverse osmosis (RO) membranes was investigated. ENRO solution (10 mg L−1, pH = 8) was irradiated under artificial light for 2 h. As a result the degradation of ENRO produced three photoproducts with molecular weights (MW) 389, 373 and 114 g mol−1. Reverse osmosis (LFC–1, SWC4+) and tight nanofiltration (NF90) membranes almost removed (>99.99%) all the compounds (parent and photodegradation products), but the other nanofiltration (DK, NF and HL) membranes removed more than 92%, with one exception (36.96% for the compound with MW 114 g mol−1) obtained using HL membrane.

Chemical diversity of the natural populations of Dalmatian pyrethrum (Tanacetum cinerariifolium /Trevir. /Sch. Bip.) in Croatia

Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch.Bip.) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households.

Farmaceutici u okolišu

Farmaceutici su spojevi koji se upotrebljavaju za lijecenje ili sprjecavanje bolesti ljudi i životinja te kao promotori rasta u veterinarskoj medic