A simple,selective,sensitive,precise,simultaneous high performance liquid chromatographic analysis of serum samples and commercial tablet formulation containing hydrochlorothiazide,olmesartan medoxomil and irbesartan ...A simple,selective,sensitive,precise,simultaneous high performance liquid chromatographic analysis of serum samples and commercial tablet formulation containing hydrochlorothiazide,olmesartan medoxomil and irbesartan are reported.Good chromatographic separation was achieved using a μ-Bondapak,C18 column(15 cm×4.6 mm,5 μm),and a mobile phase consisting of acetonitrile-0.2% acetic acid aqueous solution(50∶50,v/v)at a flow rate of 1.0 mL/min.The ultraviolet detector was set at a wavelength of 260 nm.Hydrochlorothiazide,olmesartan medoxomil,and irbesartan were eluted at 1.2,3.8,and 4.4 min,respectively.No extraneous materials were found to interfere.The method uses protein precipitation with acetonitrile for the preparation of serum sample.The linear ranges for hydrochlorothiazide,olmesartan medoxomil,and irbesartan were 6.25-18.75,20-60,and 75-225 ng/mL,respectively.The recoveries of hydrochlorothiazide,olmesartan medoxomil,and irbesartan in spiked samples were all greater than 98%,and their relative standard deviations were less than 2.0%.The limits of detection were 1,2,and 2 ng/mL for hydrochlorothiazide,olmesartan medoxomil,and irbesartan,respectively,and the limits of quantification were 3 ng/mL,which allow their determination at the expected serum concentration levels.展开更多
A highly simple, rapid, sensitive and selective method is developed for spectrophotometric determination of gabapentin in pure form as well as in pharmaceutical formulations. The method is based on the formation of a ...A highly simple, rapid, sensitive and selective method is developed for spectrophotometric determination of gabapentin in pure form as well as in pharmaceutical formulations. The method is based on the formation of a yellow Schiff base derived from the condensation of gabapentin drug (1-amino methyl) cyclo hexane acetic acid and 2,5-dihydroxybenzaldehyde (DHBA) exhibiting a maximum absorbance at 445 nm. The composition, molar absorptivity and effect of different excipient have been determined spectrophotometrically. Under optimized experimental conditions, Beer’s law is obeyed in the concentration range 2.57 - 37.25 μg/ml. The method is validated with respect to accuracy, precision, limit of detection and limit of quantification. The Sandell sensitivity, correlation coefficient and regression equation are calculated. The equilibrium constant and free energy change using Benesi-Hildebrand plot are also determined. The Schiff base derived from condensation of gabapentin with DHBA is also synthesized and characterized. The condensation reaction mechanism has been proposed.展开更多
A sensitive spectrofluorimetric method was developed for determination of ciprofloxacin (CPFX), levofloxacin (LEV), gatifloxacin (GAT) and moxifloxacin (MOX) in pure, commercial formulations, human urine and plasma. T...A sensitive spectrofluorimetric method was developed for determination of ciprofloxacin (CPFX), levofloxacin (LEV), gatifloxacin (GAT) and moxifloxacin (MOX) in pure, commercial formulations, human urine and plasma. The method is based on charge-transfer (CT) complex with chloranilic acid. Fluorescence intensity of the complexes was measured at emission wavelength ranging from 445-492 nm with excitation wavelengths from 285-330 nm. At optimum experimental conditions, a linear calibration plot was obtained in the concentration range of 20-1000 ng·mL-1, 60-320 ng·mL-1, 20-800 ng·mL-1 and 20 -00 ng·mL-1 for CPFX, LEV, MOX and GAT, respectively with good correlation coefficient in the range of 0.9929-1.0 in methanolic medium. The limit of detection and limit of quantification were found to be 5 ng·mL-1 and 18 ng·mL-1 for CPFX, 12 ng·mL-1 and 40 ng·mL-1 for LEV, 8 ng·mL-1 and 19 ng·mL-1 for MOX, 6 ng·mL-1 and 19 ng·mL-1 for GAT, respectively. The method was found free of interferences from excipients used as additive in pharmaceutical preparations, some common cations and compounds present in urine and plasma as well as co-administered analgesic, vitamins and other drugs. The method was successfully applied for quantification of selected fluoroquinolones in commercial formulations and also in spiked human urine and plasma samples with percent recoveries of 100.0 ± 1.56 and 100.2 ± 1.29 respectively.展开更多
A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that t...A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.展开更多
An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug,...An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug, pitavastatin(PST). The fabricated electrochemical sensor was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The fabricated electrode was employed in quantifying and determining PST through differential pulse adsorptive stripping voltammetry(DPAdSV) and CV. The electrode fabrication proceeded with remarkable sensitivity to the determination of PST. The effect of various optimized parameters such as pH, scan rate(ν), accumulation time(t_(acc)), accumulation potential(U_(acc))and loading volumes of Ag MP-MWCNT suspension were investigated to evaluate the performance of synthesized electrochemical sensor and to propose a simple, accurate, rapid and economical procedure for the quantification of PST in pharmaceutical formulations and biological fluids. A linear response of PST concentration in the range 2.0×10^(-7)–1.6×10^(-6)M with low detection(LOD) and quantification(LOQ) limits of 9.66 ± 0.04 nM and 32.25 ± 0.07 nM, respectively, were obtained under these optimized conditions.展开更多
The present study explores an electroreduced graphene oxide-bismuth nanoparticles composite（ErGOBi） as an electrochemical sensor for the determination of an anticancer drug, gemcitabine hydrochloride（GMB）. The Er-...The present study explores an electroreduced graphene oxide-bismuth nanoparticles composite（ErGOBi） as an electrochemical sensor for the determination of an anticancer drug, gemcitabine hydrochloride（GMB）. The Er-GOBi interface was prepared by drop casting of bismuth nitrate-graphene oxide suspension on a glassy carbon electrode（GCE） followed by electro-reduction in the potential range of 0.6 V to 1.7 V. SEM, FTIR, EDAX and AFM techniques were employed for the characterization of prepared materials. Cyclic voltammetric and electrochemical impedance spectroscopic methods were used to understand the charge transfer properties of stepwise modification of Er-GOBi/GCE. GMB exhibited an irreversible oxidation peak at 1.144 V on Er-GOBi/GCE in phosphate buffer of p H 3. A 100-fold enhanced oxidation peak current was observed at Er-GOBi/GCE when compared to that at bare GCE.Sensing performance of Er GO-Bi/GCE was optimized by varying peak current dependent parameters.Linear relationship between the peak current and concentration of GMB was observed in the range of 0.1–51.1 mmol/L in differential pulse voltammetric method and 2.1–61.1 mmol/L in linear sweep voltammetric method. The practical utility of the proposed sensor, Er-GOBi/GCE was demonstrated by determining GMB in pharmaceutical formulations and spiked urine samples.展开更多
文摘A simple,selective,sensitive,precise,simultaneous high performance liquid chromatographic analysis of serum samples and commercial tablet formulation containing hydrochlorothiazide,olmesartan medoxomil and irbesartan are reported.Good chromatographic separation was achieved using a μ-Bondapak,C18 column(15 cm×4.6 mm,5 μm),and a mobile phase consisting of acetonitrile-0.2% acetic acid aqueous solution(50∶50,v/v)at a flow rate of 1.0 mL/min.The ultraviolet detector was set at a wavelength of 260 nm.Hydrochlorothiazide,olmesartan medoxomil,and irbesartan were eluted at 1.2,3.8,and 4.4 min,respectively.No extraneous materials were found to interfere.The method uses protein precipitation with acetonitrile for the preparation of serum sample.The linear ranges for hydrochlorothiazide,olmesartan medoxomil,and irbesartan were 6.25-18.75,20-60,and 75-225 ng/mL,respectively.The recoveries of hydrochlorothiazide,olmesartan medoxomil,and irbesartan in spiked samples were all greater than 98%,and their relative standard deviations were less than 2.0%.The limits of detection were 1,2,and 2 ng/mL for hydrochlorothiazide,olmesartan medoxomil,and irbesartan,respectively,and the limits of quantification were 3 ng/mL,which allow their determination at the expected serum concentration levels.
文摘A highly simple, rapid, sensitive and selective method is developed for spectrophotometric determination of gabapentin in pure form as well as in pharmaceutical formulations. The method is based on the formation of a yellow Schiff base derived from the condensation of gabapentin drug (1-amino methyl) cyclo hexane acetic acid and 2,5-dihydroxybenzaldehyde (DHBA) exhibiting a maximum absorbance at 445 nm. The composition, molar absorptivity and effect of different excipient have been determined spectrophotometrically. Under optimized experimental conditions, Beer’s law is obeyed in the concentration range 2.57 - 37.25 μg/ml. The method is validated with respect to accuracy, precision, limit of detection and limit of quantification. The Sandell sensitivity, correlation coefficient and regression equation are calculated. The equilibrium constant and free energy change using Benesi-Hildebrand plot are also determined. The Schiff base derived from condensation of gabapentin with DHBA is also synthesized and characterized. The condensation reaction mechanism has been proposed.
文摘A sensitive spectrofluorimetric method was developed for determination of ciprofloxacin (CPFX), levofloxacin (LEV), gatifloxacin (GAT) and moxifloxacin (MOX) in pure, commercial formulations, human urine and plasma. The method is based on charge-transfer (CT) complex with chloranilic acid. Fluorescence intensity of the complexes was measured at emission wavelength ranging from 445-492 nm with excitation wavelengths from 285-330 nm. At optimum experimental conditions, a linear calibration plot was obtained in the concentration range of 20-1000 ng·mL-1, 60-320 ng·mL-1, 20-800 ng·mL-1 and 20 -00 ng·mL-1 for CPFX, LEV, MOX and GAT, respectively with good correlation coefficient in the range of 0.9929-1.0 in methanolic medium. The limit of detection and limit of quantification were found to be 5 ng·mL-1 and 18 ng·mL-1 for CPFX, 12 ng·mL-1 and 40 ng·mL-1 for LEV, 8 ng·mL-1 and 19 ng·mL-1 for MOX, 6 ng·mL-1 and 19 ng·mL-1 for GAT, respectively. The method was found free of interferences from excipients used as additive in pharmaceutical preparations, some common cations and compounds present in urine and plasma as well as co-administered analgesic, vitamins and other drugs. The method was successfully applied for quantification of selected fluoroquinolones in commercial formulations and also in spiked human urine and plasma samples with percent recoveries of 100.0 ± 1.56 and 100.2 ± 1.29 respectively.
文摘A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.
文摘An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug, pitavastatin(PST). The fabricated electrochemical sensor was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The fabricated electrode was employed in quantifying and determining PST through differential pulse adsorptive stripping voltammetry(DPAdSV) and CV. The electrode fabrication proceeded with remarkable sensitivity to the determination of PST. The effect of various optimized parameters such as pH, scan rate(ν), accumulation time(t_(acc)), accumulation potential(U_(acc))and loading volumes of Ag MP-MWCNT suspension were investigated to evaluate the performance of synthesized electrochemical sensor and to propose a simple, accurate, rapid and economical procedure for the quantification of PST in pharmaceutical formulations and biological fluids. A linear response of PST concentration in the range 2.0×10^(-7)–1.6×10^(-6)M with low detection(LOD) and quantification(LOQ) limits of 9.66 ± 0.04 nM and 32.25 ± 0.07 nM, respectively, were obtained under these optimized conditions.
基金the University Grant Commission, New Delhi, for providing financial support to carry out this study
文摘The present study explores an electroreduced graphene oxide-bismuth nanoparticles composite（ErGOBi） as an electrochemical sensor for the determination of an anticancer drug, gemcitabine hydrochloride（GMB）. The Er-GOBi interface was prepared by drop casting of bismuth nitrate-graphene oxide suspension on a glassy carbon electrode（GCE） followed by electro-reduction in the potential range of 0.6 V to 1.7 V. SEM, FTIR, EDAX and AFM techniques were employed for the characterization of prepared materials. Cyclic voltammetric and electrochemical impedance spectroscopic methods were used to understand the charge transfer properties of stepwise modification of Er-GOBi/GCE. GMB exhibited an irreversible oxidation peak at 1.144 V on Er-GOBi/GCE in phosphate buffer of p H 3. A 100-fold enhanced oxidation peak current was observed at Er-GOBi/GCE when compared to that at bare GCE.Sensing performance of Er GO-Bi/GCE was optimized by varying peak current dependent parameters.Linear relationship between the peak current and concentration of GMB was observed in the range of 0.1–51.1 mmol/L in differential pulse voltammetric method and 2.1–61.1 mmol/L in linear sweep voltammetric method. The practical utility of the proposed sensor, Er-GOBi/GCE was demonstrated by determining GMB in pharmaceutical formulations and spiked urine samples.
