Jan Krzek

Oxidative stress as an etiological factor and a potential treatment target of psychiatric disorders. Part 2. Depression, anxiety, schizophrenia and autism

The pathophysiology of psychiatric diseases, including depression, anxiety, schizophrenia and autism, is far from being fully elucidated. In recent years, a potential role of the oxidative stress has been highlighted in the pathogenesis of neuropsychiatric disorders. A body of clinical and preclinical evidence indicates that psychiatric diseases are characterized by higher levels of oxidative biomarkers and with lower levels of antioxidant defense biomarkers in the brain and peripheral tissues. In this article, we review current knowledge on the role of the oxidative stress in psychiatric diseases, based on clinical trials and animal studies, in addition, we analyze the effects of drug-induced modulation of oxidative balance and explore pharmacotherapeutic strategies for oxidative stress reduction.

Photocatalytic degradation of sulfamethoxazole in aqueous solution using a floating TiO2-expanded perlite photocatalyst

Photocatalytic degradation of an antibiotic, sulfamethoxazole (SMX), in aqueous solution using a novel floating TiO2-expanded perlite photocatalyst (EP-TiO2-773) and radiation from the near UV spectral range was studied. The process is important considering that SMX is known to be a widespread and highly persistent pollutant of water resources. SMX degradation was described using a pseudo-first-order kinetic equation according to the Langmuir-Hinshelwood model. The products of the SMX photocatalytic degradation were identified. The effect of pH on the kinetics and mechanism of SMX photocatalytic degradation was explained.

Chromatographic and electrophoretic techniques used in the analysis of triazole antifungal agents—a review

Systematic review of literature coupled with integrative research of published data for triazole antifungal agents was done. The investigated literature covered chromatographic and electrophoretic methods developed in the last 10 years (2000-2009). The aim of this review was to compare different methodologies, assess preferences in the selection of analytical methods and to find still existing analytical problems. Last decade is characterized by dynamic development of instrumental methods, that results in advance and diversity of applied analytical procedures. The main focus was given to high-performance liquid chromatography (HPLC), the technique of choice in the analysis of most of pharmaceuticals. The review includes literature on 8 triazole antifungal drugs: fluconazole, itraconazole and terconazole from the first generation and posaconazole, voriconazole, ravuconazole, isavuconazole and albaconazole classified in second generation. Investigations of pharmaceutical formulations and biological samples were considered.

Separation and characterization of ciprofloxacin, difloxacin, lomefloxacin, norfloxacin, and ofloxacin oxidation products under potassium permanganate treatment in acidic medium by UPLC-MS/MS.

A simple, sensitive and reproducible ultra-performance liquid chromatography method for determination of ciprofloxacin, difloxacin, lomefloxacin, norfloxacin and ofloxacin oxidation stability under permanganate treatment in acidic conditions at pH from 3.0 to 6.0, was developed. Chromatographic separations were carried out using the Acquity UPLC BEH C18 column; (2.1×100 mm, 1.7 μm particle size). The column was maintained at 40°C, and eluted under isocratic conditions using 83% of eluent A and 17% of eluent B over 6.5 min, at a flow rate of 0.3 mL min(-1). Eluent A: water/formic acid (0.1 v/v%); eluent B: acetonitrile/formic acid (0.1 v/v%). An oxidation process followed kinetic of the second order reaction and depended upon solution acidity. Oxidation of fluoroquinolones proceeded at piperazine moiety yielding respective hydroxy and oxo analogs, and remaining the quinolone fragment intact. Structures of products formed were assigned on a basis of UPLC/MS/MS fragmentation pathways.

Oxidative stress as an etiological factor and a potential treatment target of psychiatric disorders. Part 1. Chemical aspects and biological sources of oxidative stress in the brain

Oxidative stress is a dysfunctional state of living cells, caused by the disturbance of the pro-/antioxidative equilibrium. This dynamic equilibrium, constitutive for all aerobic organisms, is an inevitable necessity of maintaining the level of oxidative factors on non-destructive value to the cell. Among these factors reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the best known molecules. This review article shows the current state of knowledge on the chemical specificity, relative reactivity and main sources of ROS and RNS in biological systems. As a Part 1 to the report about the role of oxidative stress in psychiatric disorders (see Smaga et al., Pharmacological Reports, this issue), special emphasis is placed on biochemical determinants in nervous tissue, which predisposed it to oxidative damage. Oxidative stress can be identified based on the analysis of various biochemical indicators showing the status of antioxidant barrier or size of the damage. In our article, we have compiled the most commonly used biomarkers of oxidative stress described in the literature with special regard to potentially effective in the early diagnosis of neurodegenerative processes.

THIN-LAYER CHROMATOGRAPHY WITH DENSITOMETRY FOR THE DETERMINATION OF DIFLOXACIN AND ITS PHOTODEGRADATION PRODUCTS. KINETIC EVALUATION OF THE DEGRADATION PROCESS AND IDENTIFICATION OF PHOTOPRODUCTS BY MASS SPECTROMETRY

TLC-densitometric method was developed for determination of difloxacin (DIF) in the presence its photodegradation products. Silica gel TLC F254 plates were used as the stationary phase and methylene chloride:methanol:2-propanol:ammonia 25% (4:4:5:2, v/v/v/v) as the mobile phase. The elaborated method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The photodegradation process of DIF followed kinetics of the first order reaction for the substrate. Potential photodegradation products of DIF identified by UPLC-MS/MS are: 7-(2-aminoethylamino)-6-fluoro-1-(4-fluorophenyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, 7-amino-6-fluoro-1-(4-fluorophenyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, 6-fluoro-1-(4-fuorophenyl)-7-(3-hydroxypiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, 6-fluoro-1-(4-fuorophenyl)-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid.

Determination of sparfloxacin and its photodegradation products by thin-layer chromatography with densitometry detection. Kinetic evaluation of the degradation process and identification of photoproduct by mass spectrometry

A TLC-densitometric method was developed for the determination of sparfloxacin in the presence of its photodegradation products. Silica gel TLC F254 plates were used as the stationary phase and methylene chloride : methanol : 2-propanol : ammonia 25% (4 : 4 : 5 : 2 v/v/v/v) as the mobile phase. The developed method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The linear regression analysis for the calibration curve showed a good linear correlation over the concentration range 1.00–3.00 μg per band, with the determination coefficient, R2, exceeding 0.9958. The method was shown to have good precision and intermediate precision, as reflected by the relative standard deviation values, lower than 2.72% and characterized by a recovery rate at three concentration levels from 93.60% to 103.90%. The limits of detection and quantification were respectively 0.16 and 0.48 μg per band. The photodegradation process of sparfloxacin followed the kinetics of a first order reaction for the substrate. Nine products of photodegradation were identified by UPLC-MS/MS. The structure of a product previously not identified was determined.

Lipophilicity study of fifteen fluoroquinolones by reversed-phase thin-layer chromatography

The lipophilicity of fifteen fluoroquinolones has been investigated. Reversed-phase thin layer chromatography with densitometric detection was applied to determine the RM0 factor. The RP-TLC investigations were performed in mixtures of organic modifier–water. The partition coefficients of examined fluoroquinolones were also calculated with computational programs. All the obtained data, from experimental methods and theoretical calculations, were compared and a suitable conclusion was reached. The received results demonstrate that the RP-TLC method may be the only reliable technique for fluoroquinolones in describing their lipophilic nature as well as the activity.

Determination of danofloxacin and its photodegradation products by HPLC-DAD. Kinetic evaluation of the degradation process and identification of photoproducts by mass spectrometry

A HPLC method was developed for determination of danofloxacin (DAN) in the presence of its photodegradation products. Chromatography was performed on a Gemini-NX C18 110A, 150 mm × 4.60 mm, 3 μm particle size column with 0.025 M phosphate buffer (pH = 5.00)–acetonitrile–methanol (95 : 10 : 30 v/v/v) as the mobile phase at a flow rate of 1.2 mL min−1. UV detection was performed at 280 nm. The column was thermostatted at 25 °C. The elaborated method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The linear regression analysis for the calibration curve showed a good linear correlation over the concentration range 0.20–0.80 mg mL−1, with determination coefficient, R2, exceeding 0.9966. The method was shown to have good and intermediate precision, as reflected by the relative standard deviation values, lower than 2.21% and characterized by a recovery rate at three concentration levels from 98.0% to 101.70%. The limits of detection and quantification were respectively 0.0055 and 0.0167 mg mL−1. The photodegradation process of DAN followed kinetics of the first order reaction for the substrate. Ten products of photodegradation were identified by UPLC/MS/MS.

Roxithromycin degradation by acidic hydrolysis and photocatalysis

The purpose of this work was to study two methods of degradation of roxithromycin: acidic hydrolysis and photocatalytic degradation under illumination with near-UV light in the presence of the TiO2 photosensitizer. For acidic degradation studies a TLC-densitometric method has been developed using TLC aluminium plates precoated with silica gel F254 and the mobile phase composed of methanol–acetone–ammonia 25% (1 : 14 : 0.1, v/v/v) which gives compact spots for roxithromycin and its degradation products. Photocatalytic degradation studies in the presence of TiO2 were monitored by HPLC. The obtained results have shown that both methods of degradation of roxithromycin are quite efficient. Kinetics of the first order photocatalytic degradation reaction follows the Langmuir–Hinshelwood theory for photocatalytic microheterogeneous systems. The chemical structures of the degradation products obtained during acidic degradation and photocatalytic degradation were suggested based on the UPLC-MS/MS technique. The general mechanisms of both processes were proposed.