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In this work, the electrooxidation ability of nine pyridones was evaluated using cyclic(CV) and square-wave voltammetry (SWV) in Britton–Robinson (BR) aqueous buffer solutions on aglassy carbon electrode (GC). The dependence of electrochemical activity on pyridone structure waselucidated by means of experimentally obtained spectra and quantum chemical calculations. Firstly, itwas shown that electrochemical activity is determined by the –OH group as a substituent in position6 of the pyridone ring. By coupling the experimentally obtained UV-Vis spectra and DFT calculations,the most stable forms, both protonated and deprotonated, were defined. The calculated values areconsistent with the electrochemical behavior observed, indicating that the deprotonated anionic formwas the most electrochemically active. Moreover, the impact of the substituent in position 3 of thepyridone scaffold was discussed

The anticholinergic drug, solifenacin (SOL), is frequently used for the treatments in urological tract for urinary incontinence, and urinary frequency [1]. As an electroactive molecule, SOL can be an appropriate target analyte for voltammetric measurements. Boron doped diamond electrode (BDDE) was selected as a working electrode because of its unique electrochemical properties and emphasis on anodic measurements [2]. Prior to the voltammetric measurements of SOL, BDDE was electrochemically activated in the supporting electrolyte by anodic pretreatment (+2.0 V; 30 s) to achieve an oxygen terminated surface [3]. The voltammetric behavior of SOL was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in a model system. Based on the CV measurements it is proved that the certain electrooxidation process is diffusion controlled. Various experimental parameters were optimized including the pH of the aqueous Britton-Robinson (B-R) buffer as a supporting electrolyte (from pH 2.0 to 11.98) in the potential range from -0.3 V to 1.6 V vs saturated calomel electrode. Depending on the pH value of the B-R buffer one oxidation peak of SOL was obtained at maxima of peak potential around 1.1 V. The most intensive peak of the target analyte was at pH 11.0 which was chosen as an optimal pH value for further measurements. Based on the correlation of SOL peak intensity and different concentrations, the developed DPV method was characterized by a linear concentration range from 0.015 to 0.907 µg mL-1, coefficient correlation of 0.999, and relative standard deviation of 0.33%. Taking into account the sensitivity of the developed DPV method towards the electrochemical oxidation of SOL, a very low detection limit of 0.005 µg mL-1 in the model system is achieved. The BDDE showed adequate selectivity for SOL in the presence of investigated interferents. The obtained results indicate that BDDE with an optimized DPV method could be applied for the trace-level electro

Sistem i postupak automatske klasifikacije UV/VIS signala radi dijagnostike bilijarne ciroze i njihova primena okarakterisani su prema ovom pronalasku time što se preko USB memorije (120) unosi UV/VIS signal u sistem (100), označava u fazi (c), filtrira u fazi (d), izdvajaju karakteristična obeležja u fazi (e), klasifikuje u fazi (f), unosi u blok (106) za formiranje izveštaja, trajno memoriše u fazi (h) i prikazuje na LCD ekranu (110). Primena ovog sistema i postupka za automatsku klasifikaciju UV/VIS signala radi dijagnostike bilijarne ciroze je u tome što se koristi kao dijagnostički protokol pri utvrđivanju oboljenja u humanoj medicini., A system and method for automatic classification of UV/VIS signals in diagnostics of biliary cirrhosis and their application according this invention in which USB memory (120) UV/VIS signal which introduce in system (100), designates in phase (c), filtrate in phase (d), separate assignments in phase (e), classification in phase (f), introduce in block (106) for forming report, permanent memorize in phase (h) and appears on LCD display (110). The application of this system and method for automatic classification of UV/VIS signals in diagnostics of biliary cirrhosis is in diagnostic protocol for estimate diseases in human medicine.

In this work, the electrooxidation ability of nine pyridones was evaluated using cyclic (CV) and square-wave voltammetry (SWV) in Britton–Robinson (BR) aqueous buffer solutions on a glassy carbon electrode (GC). The dependence of electrochemical activity on pyridone structure was elucidated by means of experimentally obtained spectra and quantum chemical calculations. Firstly, it was shown that electrochemical activity is determined by the –OH group as a substituent in position 6 of the pyridone ring. By coupling the experimentally obtained UV-Vis spectra and DFT calculations, the most stable forms, both protonated and deprotonated, were defined. The calculated values are consistent with the electrochemical behavior observed, indicating that the deprotonated anionic form was the most electrochemically active. Moreover, the impact of the substituent in position 3 of the pyridone scaffold was discussed

Duloxetine hydrochloride ( D U L ) , a naphth) I ether amine, inhibits the uptake of serotonin and norepinephrine. The electrochemical behavior of D U L was determined by cyclic voltammetry ( C V ) in phosphate buffer solution at gold electrode by varying pH and scan rate. The electroanalytical application was studied with the aid of differential pulse voltammetry (DPV) in sodium bicarbonate solution. A linear response ranged from 5x10'^ M to 10'" M. The validation of the DPV method was carried out by determine of the limit of detection (LOD) and limit of quantitation (LOQ) and the calculate values were 4.6 X 10"'' and 2 x 10'^' M, respective!). The proposed DPV method has been successfully applied to assessment DUL as standard and in Taita® tablets and standard spiked with human serum.

In this study the electrochemical behavior of metformin (MET), oral antihyperglycaemic agent, was assayed at three different electrodes. The drug standard was investigated by cyclic voltammetry (CV) and square wave volta-mmetry (SWV) via its electrooxidation at Au and glassy carbon (GC) electrode in 0.05 M NaHCO3. Under these conditions transformation of MET to corresponding N-carbonyl guanidine via oxime intermediate is suggested. The stability of MET was tested under directed stress conditions using IrOx elec-trode with sodium sulphate as an electrolyte and cyclic 4-amino-2-imino-1-me-thyl-1,2-dihydro-1,3,5-triazine (4,2,1-AIMT) appeared as the main end-product. The courses of the electrochemical processes at three electrodes are followed by UV spectroscopy and evaluated by total organic carbon (TOC) analysis.

Esomeprazole is the most effective of the proton-pump inhibitors for the acid-related diseases and at first was examined for the electroanalytical purposes. The drug standard and as a content of injection powder was investigated by cyclic voltammetry (CV) and quantitatively determined using square wave voltammetry (SWV) via its electrooxidation at Au electrode in 0.05 M NaHCO3. SWV showed a linear dependency of the anodic peak currents vs. esomeprazole standard concentrations in the range from 3.0 to 500 mu g mL(-1) with the values of limit of detection (LOD) and limit of quantification (LOQ): 1.4 and 4.6 mu g mL(-1), respectively. Using the constructed and validated calibration curve, the values of unknown esomeprazole concentrations in injection powder and in human serum spiked with standard were determined. Before the electrochemical oxidation, it was shown by atomic force microscopy (AFM) that the small esomeprazole islands formed inside holes were visible and their diameter was about 200 nm attributed to physico-chemical characteristics of esomeprazole. After the electrochemical oxidation, the morphology of esomeprazole standard on Au surface was completely changed and composed of spherical particles in a diameter between 200 and 600 nm. With esomeprazole suspended in human serum, the process of crystallization partly occurred in the form of spherical grains with the average size of these grains was about 4 gm. The analysis at the macro level done by the optical microscopy (OM) confirmed this opinion. The study of esomeprazole degradation showed that at Au electrode, after 3 h of cycling, a neglectable amount of the esomeprazole was changed. Using IrOx electrode under directed stress conditions, its almost complete degradation was realized after 3 h confirmed by high performance liquid chromatography (HPLC). Total organic carbon (TOC) analysis showed that 95% of esomeprazole was mineralized. The HPLC and Liquid chromatography-mass spectrometry (LC-MS) study rev

The inclusion complexes of the selected, potentially biologically active, succinimides with beta-cyclodextrin (beta CD) and (2-hydroxypropyl)-beta-cyclodextrin (HP beta CD) were prepared. The formation of the inclusion complexes of the investigated monophenyl and diphenyl succinimide derivatives was confirmed using attenuated total reflection (ATR) study. Their electrochemical behavior was examined by cyclic voltammetry (CV) and square wave voltammetry (SWV) in 0.05 M NaHCO3 on a gold electrode. The stability constants for compound 1 were determined by cyclic voltammetry and calculated as K-beta CD = 350.87 M-1 and K-HP(beta CD) = 250.67 M-1. The SWV measurements reveal well defined peak at potential E-p = similar to 60 mV and the higher currents at E-p for both inclusion complex of the succinimides compared to the free compounds. The impact of chlorine atom in the phenyl moiety of succinimide derivatives on the activity in electro oxidation reaction is presented. Among the studied succinimides, according to SWV measurements, the most active is the monophenyl succinimide derivative (compound 1) in complex with beta CD. The difference of peak current of compound 1 + beta CD compared to compound 1 + HP beta CD and free compound is 6.3 and 35.2 mu A cm(-2), respectively.

The constant need to find an increasing number of diagnostic more selective techniques by which we would be able to determine an altered substrate as characteristic of the disease suspected is everyday clinical problem. It is important to note that diagnostic failure is the main cause of unnecessary costs that account for about 35% funds intended for healing in funds. The greatest number of people will experience at least one diagnostic error during their lifetime. The already realized results concerning new invented UV-vis method and automatic classification of the obtained spectroscopic signals in diagnostics of different diseases led to the the invention and construction of Computer-Aided Decision-Assistant system for Diagnosis of Different Diseases. It was achieved by automatization of UV-vis signals of different body fluids without or with known official diagnosis. In the invention and construction of this system is included clinical work, the softwer and hardwer realization, design and logo. Results included into the realization of constructed prototype will be presented.

Electrochemical behavior of sildenafil citrate (SC) at gold and cystein (Cys) modified gold electrode (AulCys) in 0.1 M H2SO4 was investigated by cyclic voltammetry (CV) and by square wave voltammetry (SWV). Effect of scan rate on the CVs of SC standard was performed in order to examine the mode of transport and irreversibility of process. SC as standard is determined by SWV in acid solution at Au electrode in a range: 10(-3), 10(-2) 0.1, 0.5, 1 mu M and on Au/Cys in a range: 10(-3), 10(-2) 0.05, 0.1 mu M. The presence of Cys causes two-time larger peak currents and shifting of the incipient potential of the SC oxidation to 0.1 V in negative direction. In investigated range of concentration of SC standard in acid solution on modified and unmodified Au electrodes SWV method have excellent linear regression coefficient with value 0.997 promoting SWV for reliable determination of SC.

Esomeprazole has been shown to be the most effective oral PPI for controlling intragastric pH. The persistence of esomeprasole in environmental systems could be solved by different types of its degradation. In this work electrocatalytic degradation of esomeprasole has been investigated in the presence of sodium sulfate and sodium chloride using IrOx electrode and was monitored using UV-Vis spectrophotometer at 303 nm. Also the electro degradation process was examined and on Au electrode. NanoScope III A (Veeco, USA) microscope was used to study the morphology of Esomeprazole on the gold surface by atomic force microscopy. By optical microscopy the morphology of Esomeprazole dissolved in human serum on the gold surface was studied as well., Ezomeprazol je poznat kao najefikasniji lek , tj. inhibitor protonske pumpe u kontroli intragastricne vrednosti pH. Njegovo prisustvo u vodenim tokovima i zemljištu se resava osmišljavanjem novih postupaka degradacije. U ovom radu elektrokatalitiþka degradacija ezomeprazola je prouþavana u natrijum sulfatu i natrijum hloridu na IrOx elektrodi. Reakcija je praüena korišüenjem UV-Vis spektrofotometra na 303 nm. Takoÿe je prouþavana degradacija ezomeprazola na elektrodi od zlata. NanoScope III A (Veeco, USA) mikroskop je korišüen u prouþavanju morfologije ezomeprazola na površini eelektrode od zlata mikroskopijom mneÿuatomskih sila. Optiþkom mikroskopijom je ispitivana morfologija ezomeprazola na površini eelektrode od zlata u prisustvu humanog seruma.

Tebuconazole, a pesticide that presents risks for ecosystems, groundwater and human health, was degraded on a gold electrode as the catalyst in 0.05 M NaHCO3 using cyclic voltammetry (CV). First, tebuconazole was characterized on the gold electrode using CV and square wave voltammetry (SWV). The gold electrode, being highly sensitive, provided linear relationships (currents vs. concentrations) in the range: (0.076-0.76 mu mol dm(-3)). Based on the CV measurements, the investigated process is irreversible and diffusion controlled. The observed catalytic role of the Au electrode in the oxidation of tebuconazole and the data obtained from CV and SWV provided the experimental conditions for the degradation of tebuconazole. The degradation was performed by continuous cycling followed by gas chromatography mass spectroscopy (GC MS) analysis. This enabled the catalytic elimination of tebuconazole for 60 min, which promoted the use of a gold electrode as the catalyst for the degradation of environmental pollutants. The scheme of the possible mechanism of tebuconazole degradation is given.

Nonmedical use of sildenafil citrate (SC) requires new methods for drug determination in human serum and in tablets. SC as standard and in Sildena (R) tablets is determined by square wave voltammetry (SWV) in 0.1 M H2SO4 (harmful for human serum) at gold electrode in a range: (1 x 10(-3),1 x 10(-2), 0.1, 0.5,1) mu M and on cysteine (Cys) modified gold electrode (Au/Cys) in a range: (1 x 10(-3),1 x 10(-2), 0.05, 0.1) mu M. The presence of Cys causes two times larger peak currents and shifting of the incipient potential of the SC oxidation to 0.1 V in negative direction. A safe procedure for SC determination as standard and in Sildena (R) tablets spiked with human serum is developed by SWV at gold electrode in 0.05 M NaHCO3 (suitable for human liquids) in a range: (1 x 10(-3),1 x 10(-2), 0.1, 0.2, 03) mu M. Microscopic characterization of the surfaces morphology was also performed. The SC concentrations were checked by high performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV) showing that electrochemical method is more sensitive and can be used for the measurements of very low concentrations of the analyte.

The electrochemical behavior of phenobarbital sodium (PBS), paracetamol (PCM) and their binary mixtures was investigated using cyclic voltammetry (CV) and square wave voltammetry (SWV) at a bare gold electrode in a 0.05 M bicarbonate solution. A calibration curve of PBS obtained by SWV had two linear ranges, from 1.0 to 3.0 mu M and from 5.0 to 35.0 mu M with a limit of quantification (LOQ) of 0.62 mu M and a limit of detection (LOD) of 0.19 mu M, while a calibration curve of PCM was determined within the range from 10.0 to 50.0 mu M with a LOQ of 8.53 mu M and a LOD of 2.56 mu M. Both drugs underwent oxidation by irreversible, diffusion controlled process. The SW voltammograms of the drug mixtures produced complex, overlapping profiles and a chemometric method was applied for their decomposition. Two different artificial neural network (ANN) architectures, namely back-propagation neural network (BPNN) and general regression neural network (GRNN) were employed for the simultaneous prediction of the concentrations of the drugs in a synthetic sample. The BPNN model had higher accuracy (mean absolute percentage error values were in the range of 3.6-8.4%) and thus it can be used for the simultaneous determination of PBS and PCM.

Electrochemistry is rapidly growing area with a number of possible applications in the pharmaceutical analysis. Modern electrochemical methods are selective, sensitive, rapid, and provide easy techniques applicable to analyses in the pharmaceutical fi eld. It is evident that the electroanalytical techniques at varying levels of sensitivity are required to solve analytical–pharmaceutical problems. The advantages of electrochemical methods are the simple procedures of the sample preparation and in most cases lack of interferences from excipients in the pharmaceutical dosage forms.