A comprehensive review with 276 references for the analysis of members of an important class of drugs, cephalosporin antibiotics, is presented. The review covers most of the methods described for the analysis of these drugs in pure forms, in different pharmaceutical dosage forms and in biological fluids.

A comprehensive review with 276 references for the analysis of members of an important class of drugs, cephalosporin antibiotics, is presented. The review covers most of the methods described for the analysis of these drugs in pure forms, in different pharmaceutical dosage forms and in biological fluids.

Sweeping is an important online focusing method in capillary zone electrophoresis and electrokinetic chromatography, which is employed in numerous methods for analyte enrichment and improvement of detection and quantitation limits. This review intends to summarize the present state of developments in the understanding of sweeping processes with special emphasis on the modeling of moving and stationary boundaries with assumed moving and/or stationary accelerating or decelerating planes. Starting from the description of sweeping for a neutral analyte under homogeneous field conditions, it is shown that the methodology of modelling zone focusing processes with moving and/or stationary accelerating or decelerating planes allows extending the description to charged analytes, inhomogeneous field conditions, retention factor gradient effect conditions, complex formation ligand as sweeping carrier and dynamic pH junction conditions. The present article introduces a generalized theoretical basis that allows a better understanding of the various factors influencing sweeping processes. The discussion is completed with a section on limitations of the presented approach.

A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2-modified graphite electrode. Two different MnO2 polymorphs (g- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2 /g, which is extremely high if compared to that of g-MnO2 NPs (38 m2 /g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either g- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025e3.60 mmol L1 LED with a low limit of detection, which was found to be 5.10 nmol L1 (4.50 ng mL1 ) for the 1st peak and 9.20 nmol L1 (8.10 ng mL1 ) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-

A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2-modified graphite electrode. Two different MnO2 polymorphs (g- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2 /g, which is extremely high if compared to that of g-MnO2 NPs (38 m2 /g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either g- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025e3.60 mmol L1 LED with a low limit of detection, which was found to be 5.10 nmol L1 (4.50 ng mL1 ) for the 1st peak and 9.20 nmol L1 (8.10 ng mL1 ) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-

A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2-modified graphite electrode. Two different MnO2 polymorphs (g- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2 /g, which is extremely high if compared to that of g-MnO2 NPs (38 m2 /g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either g- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025e3.60 mmol L1 LED with a low limit of detection, which was found to be 5.10 nmol L1 (4.50 ng mL1 ) for the 1st peak and 9.20 nmol L1 (8.10 ng mL1 ) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-

A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2-modified graphite electrode. Two different MnO2 polymorphs (g- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2 /g, which is extremely high if compared to that of g-MnO2 NPs (38 m2 /g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either g- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025e3.60 mmol L1 LED with a low limit of detection, which was found to be 5.10 nmol L1 (4.50 ng mL1 ) for the 1st peak and 9.20 nmol L1 (8.10 ng mL1 ) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-

Background: Atorvastatin (ATOR) is an antihyperlipoproteinemic drug, (3R, 5R)-7-[2-(4- fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-(propan-2-yl)-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid (Fig. 1a). It is used for the treatment of dyslipidemia and for prevention of different cardiovascular disorders. Methods: A simple and sensitive analytical procedure has been developed, optimized and validated by square wave voltammetry (SWV) using pencil graphite electrode (PGE) for the determination of atorvastatin calcium (ATOR) in both pharmaceutical formulation and biological samples. The voltammetric behavior of ATOR is studied using cyclic and square wave voltammetry in the presence of the ionic liquid-based surfactant, 1-tetradecyl-3-methylimidazolium bromide (C14MImBr). Results: The effect of different factors on the oxidation peak current of ATOR have been studied and optimized such as: pH, scan rate and the concentration of C14MImBr. Under optimized conditions in Britton–Robinson buffer (pH 3.3) containing 28 µmol L-1 C14MImBr, a linear response is obtained within the range of 1.34x10-6 to 10.8x10-6 mol L-1 ATOR, which is adequate for the quantitation of ATOR in real samples. The limit of detection was found to be 3.70x10-8 mol L-1. In addition, the developed method was applied to ATOR analysis in Lipitor tablets and spiked urine samples. Conclusion: This study represents the first report of electrochemical analysis of a pharmaceutical compound using ionic liquid-based surfactant. The analytical signal of ATOR is greatly enhanced in the presence of C14MImBr if compared to that obtained using a traditional cationic surfactant cetyltrimethylammonium bromide (CTAB).

Background: Atorvastatin (ATOR) is an antihyperlipoproteinemic drug, (3R, 5R)-7-[2-(4- fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-(propan-2-yl)-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid (Fig. 1a). It is used for the treatment of dyslipidemia and for prevention of different cardiovascular disorders. Methods: A simple and sensitive analytical procedure has been developed, optimized and validated by square wave voltammetry (SWV) using pencil graphite electrode (PGE) for the determination of atorvastatin calcium (ATOR) in both pharmaceutical formulation and biological samples. The voltammetric behavior of ATOR is studied using cyclic and square wave voltammetry in the presence of the ionic liquid-based surfactant, 1-tetradecyl-3-methylimidazolium bromide (C14MImBr). Results: The effect of different factors on the oxidation peak current of ATOR have been studied and optimized such as: pH, scan rate and the concentration of C14MImBr. Under optimized conditions in Britton–Robinson buffer (pH 3.3) containing 28 µmol L-1 C14MImBr, a linear response is obtained within the range of 1.34x10-6 to 10.8x10-6 mol L-1 ATOR, which is adequate for the quantitation of ATOR in real samples. The limit of detection was found to be 3.70x10-8 mol L-1. In addition, the developed method was applied to ATOR analysis in Lipitor tablets and spiked urine samples. Conclusion: This study represents the first report of electrochemical analysis of a pharmaceutical compound using ionic liquid-based surfactant. The analytical signal of ATOR is greatly enhanced in the presence of C14MImBr if compared to that obtained using a traditional cationic surfactant cetyltrimethylammonium bromide (CTAB).

Background: Atorvastatin (ATOR) is an antihyperlipoproteinemic drug, (3R, 5R)-7-[2-(4- fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-(propan-2-yl)-1H-pyrrol-1-yl]-3,5-dihydroxyheptanoic acid (Fig. 1a). It is used for the treatment of dyslipidemia and for prevention of different cardiovascular disorders. Methods: A simple and sensitive analytical procedure has been developed, optimized and validated by square wave voltammetry (SWV) using pencil graphite electrode (PGE) for the determination of atorvastatin calcium (ATOR) in both pharmaceutical formulation and biological samples. The voltammetric behavior of ATOR is studied using cyclic and square wave voltammetry in the presence of the ionic liquid-based surfactant, 1-tetradecyl-3-methylimidazolium bromide (C14MImBr). Results: The effect of different factors on the oxidation peak current of ATOR have been studied and optimized such as: pH, scan rate and the concentration of C14MImBr. Under optimized conditions in Britton–Robinson buffer (pH 3.3) containing 28 µmol L-1 C14MImBr, a linear response is obtained within the range of 1.34x10-6 to 10.8x10-6 mol L-1 ATOR, which is adequate for the quantitation of ATOR in real samples. The limit of detection was found to be 3.70x10-8 mol L-1. In addition, the developed method was applied to ATOR analysis in Lipitor tablets and spiked urine samples. Conclusion: This study represents the first report of electrochemical analysis of a pharmaceutical compound using ionic liquid-based surfactant. The analytical signal of ATOR is greatly enhanced in the presence of C14MImBr if compared to that obtained using a traditional cationic surfactant cetyltrimethylammonium bromide (CTAB).