Simultaneous determination of carbaryl and 1-naphthol by first-derivative synchronous non-protected room temperature phosphorescence

The applicability of non-protected room temperature phosphorescence (NP-RTP) in real samples was demonstrated in the present work. In this methodology, only two reagents, potassium iodide and sodium sulfite, were used to obtain phosphorescent signals. Overlapping of the phosphorescence spectra was resolved by using first-derivative synchronous phosphorimetry. The synchronous first-derivative spectra of carbaryl and 1-naphthol in the mixture were completely separated by changing the synchronous wavelength interval; with 240 nm the first-derivative spectra of carbaryl were recorded, while with 200 nm those of 1-naphthol appeared. The intensities in the spectra were proportional to the concentration of carbaryl and 1-naphthol. The calibration graphs were linear up to at least 1.1 × 10 -5 mol L -1 for carbaryl and 1.3 × 10 -5 mol L -1 for 1-naphthol, and the correlation coefficients were 0.9971 and 0.9932, respectively. Carbaryl and 1-naphthol were successfully determined by the proposed method in a hydrolyzed sample of a commercial formulation.Facultad de Ciencias Exacta

Indirect fluorometric determination of diclofenac sodium

A simple and easy method of analysis for diclofenac sodium is reported. A spectrofluorometric method for the microdetermination of diclofenac sodium has been developed through its reaction with cerium(IV) in an acidic solution and measurement of the fluorescence of the Ce(III) ions produced. Under the optimum experimental conditions for the oxidation reaction, 1.0 M H 2 SO 4 with 90 min of heating time (100°C), the range of application is 124.3 - 600 ng mL -1 and the limit of detection is 72.7 ng mL -1 . The proposed method was applied to the determination of diclofenac sodium in pharmaceutical tablets. The results of the analysis show a good agreement with those obtained by the official USP 27 HPLC method.Facultad de Ciencias Exacta

Indirect fluorometric determination of diclofenac sodium

A simple and easy method of analysis for diclofenac sodium is reported. A spectrofluorometric method for the microdetermination of diclofenac sodium has been developed through its reaction with cerium(IV) in an acidic solution and measurement of the fluorescence of the Ce(III) ions produced. Under the optimum experimental conditions for the oxidation reaction, 1.0 M H 2 SO 4 with 90 min of heating time (100°C), the range of application is 124.3 - 600 ng mL -1 and the limit of detection is 72.7 ng mL -1 . The proposed method was applied to the determination of diclofenac sodium in pharmaceutical tablets. The results of the analysis show a good agreement with those obtained by the official USP 27 HPLC method.Facultad de Ciencias Exacta

Fotoluminiscencia del indol y derivados posibilidades analíticas

El presente estudio está orientado a verificar los diversos datos experimentales, no siempre concordantes, establecidos por diferentes autores relativos al proceso de absorción del indol (o indoles) en el ultravioleta, a hacer uso de valores que no son accesibles por experiencias en nuestro laboratorio -como los que surgen de procesos que ocurren en la escala de los nanosegundos-. y complementarlos con el estudio de fluorescencia y fosforescencia bajo efectos perturbadores: solventes, metilación, temperatura ,átomos pesados. Correlacionando los fenómenos de absorción y emisión será posible intentar interpretar, sobre la base de los valores encontrados, el proceso en sus aspectos energéticos y dinámicos. La interpretación, junto con los datos espectroscópicos, son específicamente importantes en relación con el comportamiento del triptofano en estado excitado y la fluorescencia de proteínas. Además, desde el punto de vista analítico, se pueden adecuar las condiciones para mejorar la sensibilidad y selectividad de las determinaciones que involucren residuos de proteínas que contengan el grupo cromóforo indólico.Tesis digitalizada en SEDICI gracias a la Biblioteca Central de la Facultad de Ciencias Exactas (UNLP).Facultad de Ciencias Exacta

A possible role of oxidative stress in the vanadium-induced cytotoxicity in the MC3T3E1 osteoblast and UMR106 osteosarcoma cell lines

The cytotoxicity and free radical production induced by vanadium compounds were investigated in an osteoblast (MC3T3E1) and an osteosarcoma (UMR106) cell lines in culture. Vanadate induced cell toxicity, reactive oxygen species (ROS) formation and thiobarbituric acid reactive substances (TBARS) increased in a concentration-dependent manner (0.1–10 mM) after 4 h. The concentration–response curve of vanadate-induced cytotoxicity and oxidative stress in MC3T3E1 cells was shifted to the left of the UMR106 curve, suggesting a greater sensitivity of the non-transformed cells in comparison to the osteosarcoma UMR106 cells. Supplementing with vitamin E acetate (80 mM) significantly inhibited ROS and TBARS formation but did not improve the vanadate-dependent decrease in cell number. Other vanadium compounds (vanadyl, pervanadate, and VO:Aspi, a complex of vanadyl(IV) with aspirin) showed different degrees of cell toxicity and induced oxidative stress. Altogether these results suggest that oxidative stress is involved in vanadium induced osteoblastic cytotoxicity, although the mechanism is unknown. © 2000 Elsevier Science Ireland Ltd. All rights reserved

Indirect fluorometric determination of diclofenac sodium

A simple and easy method of analysis for diclofenac sodium is reported. A spectrofluorometric method for the microdetermination of diclofenac sodium has been developed through its reaction with cerium(IV) in an acidic solution and measurement of the fluorescence of the Ce(III) ions produced. Under the optimum experimental conditions for the oxidation reaction, 1.0 M H 2 SO 4 with 90 min of heating time (100°C), the range of application is 124.3 - 600 ng mL -1 and the limit of detection is 72.7 ng mL -1 . The proposed method was applied to the determination of diclofenac sodium in pharmaceutical tablets. The results of the analysis show a good agreement with those obtained by the official USP 27 HPLC method.Facultad de Ciencias Exacta

Simultaneous determination of carbaryl and 1-naphthol by first-derivative synchronous non-protected room temperature phosphorescence

The applicability of non-protected room temperature phosphorescence (NP-RTP) in real samples was demonstrated in the present work. In this methodology, only two reagents, potassium iodide and sodium sulfite, were used to obtain phosphorescent signals. Overlapping of the phosphorescence spectra was resolved by using first-derivative synchronous phosphorimetry. The synchronous first-derivative spectra of carbaryl and 1-naphthol in the mixture were completely separated by changing the synchronous wavelength interval; with 240 nm the first-derivative spectra of carbaryl were recorded, while with 200 nm those of 1-naphthol appeared. The intensities in the spectra were proportional to the concentration of carbaryl and 1-naphthol. The calibration graphs were linear up to at least 1.1 × 10 -5 mol L -1 for carbaryl and 1.3 × 10 -5 mol L -1 for 1-naphthol, and the correlation coefficients were 0.9971 and 0.9932, respectively. Carbaryl and 1-naphthol were successfully determined by the proposed method in a hydrolyzed sample of a commercial formulation.Facultad de Ciencias Exacta

Osteogenic activity of vanadyl(IV)–ascorbate complex: evaluation of its mechanism of action

We have previously shown that different vanadium(IV) complexes regulate osteoblastic growth. Since vanadium compounds are accumulated in vivo in bone, they may affect bone turnover. The development of vanadium complexes with different ligands could be an alternative strategy of use in skeletal tissue engineering. In this study, we have investigated the osteogenic properties of a vanadyl(IV)–ascorbate (VOAsc) complex, as well as its possible mechanisms of action, on two osteoblastic cell lines in culture. VOAsc (2.5–25 M) significantly stimulated osteoblastic proliferation (113–125% basal, p < 0.01) in UMR106 cells, but not in the MC3T3E1 cell line. VOAsc (5–100 M) dose-dependently stimulated type-I collagen production (107–156% basal) in osteoblasts. After 3 weeks of culture, 5–25 M VOAsc increased the formation of nodules of mineralization in MC3T3E1 cells (7.7–20-fold control, p < 0.001). VOAsc (50–100 M) significantly stimulated apoptosis in both cell lines (170–230% basal, p < 0.02–0.002), but did not affect reactive oxygen species production. The complex inhibited alkaline and neutral phosphatases from osteoblastic extracts with semi-maximal effect at 10 M doses. VOAsc induced the activation and redistribution of P-ERK in a time- and dose-dependent manner. Inhibitors of the mitogen activated protein kinases (MAPK) pathway (PD98059 and UO126) partially blocked the VOAsc-enhanced osteoblastic proliferation and collagen production. In addition, wortmanin, a PI-3-K inhibitor and type-L channel blocker nifedipine also partially abrogated these effects of VOAsc on osteoblasts. Our in vitro results suggest that this vanadyl(IV)–ascorbate complex could be a useful pharmacological tool for bone tissue regeneration

Osteogenic activity of vanadyl(IV)-ascorbate complex: evaluation of its mechanism of action

We have previously shown that different vanadium(IV) complexes regulate osteoblastic growth. Since vanadium compounds are accumulated in vivo in bone, they may affect bone turnover. The development of vanadium complexes with different ligands could be an alternative strategy of use in skeletal tissue engineering. In this study, we have investigated the osteogenic properties of a vanadyl(IV)–ascorbate (VOAsc) complex, as well as its possible mechanisms of action, on two osteoblastic cell lines in culture. VOAsc (2.5–25 M) significantly stimulated osteoblastic proliferation (113–125% basal, p < 0.01) in UMR106 cells, but not in the MC3T3E1 cell line. VOAsc (5–100 M) dose-dependently stimulated type-I collagen production (107–156% basal) in osteoblasts. After 3 weeks of culture, 5–25 M VOAsc increased the formation of nodules of mineralization in MC3T3E1 cells (7.7–20-fold control, p < 0.001). VOAsc (50–100 M) significantly stimulated apoptosis in both cell lines (170–230% basal, p < 0.02–0.002), but did not affect reactive oxygen species production. The complex inhibited alkaline and neutral phosphatases from osteoblastic extracts with semi-maximal effect at 10 M doses. VOAsc induced the activation and redistribution of P-ERK in a time- and dose-dependent manner. Inhibitors of the mitogen activated protein kinases (MAPK) pathway (PD98059 and UO126) partially blocked the VOAsc-enhanced osteoblastic proliferation and collagen production. In addition, wortmanin, a PI-3-K inhibitor and type-L channel blocker nifedipine also partially abrogated these effects of VOAsc on osteoblasts. Our in vitro results suggest that this vanadyl(IV)–ascorbate complex could be a useful pharmacological tool for bone tissue regeneration.Facultad de Ciencias Exacta

Osteogenic activity of vanadyl(IV)-ascorbate complex: evaluation of its mechanism of action

We have previously shown that different vanadium(IV) complexes regulate osteoblastic growth. Since vanadium compounds are accumulated in vivo in bone, they may affect bone turnover. The development of vanadium complexes with different ligands could be an alternative strategy of use in skeletal tissue engineering. In this study, we have investigated the osteogenic properties of a vanadyl(IV)–ascorbate (VOAsc) complex, as well as its possible mechanisms of action, on two osteoblastic cell lines in culture. VOAsc (2.5–25 M) significantly stimulated osteoblastic proliferation (113–125% basal, p < 0.01) in UMR106 cells, but not in the MC3T3E1 cell line. VOAsc (5–100 M) dose-dependently stimulated type-I collagen production (107–156% basal) in osteoblasts. After 3 weeks of culture, 5–25 M VOAsc increased the formation of nodules of mineralization in MC3T3E1 cells (7.7–20-fold control, p < 0.001). VOAsc (50–100 M) significantly stimulated apoptosis in both cell lines (170–230% basal, p < 0.02–0.002), but did not affect reactive oxygen species production. The complex inhibited alkaline and neutral phosphatases from osteoblastic extracts with semi-maximal effect at 10 M doses. VOAsc induced the activation and redistribution of P-ERK in a time- and dose-dependent manner. Inhibitors of the mitogen activated protein kinases (MAPK) pathway (PD98059 and UO126) partially blocked the VOAsc-enhanced osteoblastic proliferation and collagen production. In addition, wortmanin, a PI-3-K inhibitor and type-L channel blocker nifedipine also partially abrogated these effects of VOAsc on osteoblasts. Our in vitro results suggest that this vanadyl(IV)–ascorbate complex could be a useful pharmacological tool for bone tissue regeneration.Facultad de Ciencias Exacta