RESUMO
Rapid development of the industrial and domestic sectors has led to the rise of several energy and environmental issues. In accordance with sustainable development and waste minimization issues, biohydrogen production along with biomethane production via two-stage fermentation process using microorganisms from renewable sources has received considerable attention. In the present study, biohythane production with simultaneous wastewater treatment was studied in a two-stage (Biohydrogen and Biomethane) fermentation process under anaerobic conditions. Optimization of high organic content (COD) distillery spent wash effluent (DSPW) with dilution using sewage wastewater was carried out. Addition of leachate as a nutrient source was also studied for effective biohythane production. The experimental results showed that the maximum biohythane production at optimized concentration (substrate concentration of 60 g/L with 30% of leachate as a nutrient source) was 67 mmol/L bio-H2 and with bio-CH4 production of 42 mmol/L. Graphical Abstract.
Assuntos
Biocombustíveis , Fermentação , Esgotos , Águas Residuárias , Poluentes Químicos da Água , Anaerobiose , Reatores Biológicos , Hidrogênio , Metano/biossínteseRESUMO
The upsurge in the concerning issues like global warming, environmental pollution and depletion of fossil fuel resources led to the thrust on third generation biofuels. Algal research has gained a lot of importance in the recent years. Effective utilization of algal biomass in a single step is necessary as it can produce Bio-oil (BO), gases and in addition to a variety of valuable products, along with nutrient recovery. Hydrothermal liquefaction technology does not require the energy intensive drying steps and is an attractive approach for the conversion of algae to liquid fuels. This study investigates direct hydrothermal liquefaction (HTL) of microalgae (Algal biomass) to produce bio-oil using a high-pressure batch reactor under subcritical water conditions. Three different micro algae samples namely, Chlorella vulgaris, Botryococcus braunii and Scenedesmus quadricauda have been examined under hydrothermal liquefaction with different water concentrations (1:6, 1:7, 1:8, 1:9 & 1:10 ratio) at certain temperature range (200-320⯰C), pressure (60 bars) and reaction time (30â¯min). Through liquefaction, the highest BO yield achieved with S. quadricauda was 18â¯wt% at 1:9 ratio. The chemical components of the obtained bio-oil were analyzed via gas chromatography and the results indicated that the algal BO was composed of furan, phenol, acid, and ester derivatives. Moreover, it was found that by increasing the temperatures, the BO yields increased. This was due to the polymerization reactions that converted the small biomass components into heavier molecules. FTIR spectra showed high percentage of Aliphatic, Phenolic, alcoholic, Carboxylic and Hydroxyl groups for solid residues.
Assuntos
Microalgas/metabolismo , Óleos de Plantas/química , Polifenóis/biossíntese , Polifenóis/química , Temperatura , Água/química , Biomassa , Chlorella vulgaris/metabolismo , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
BACKGROUND: Alkynes are fundamental building blocks in synthetic chemistry with high pharmaceutical applications. Among the bioactive acetylenic molecules, propargylic alcohol is most important as almost all the marketed drugs contains quaternary centered propargylic alcohol functionality. OBJECTIVE: In this study we have synthesised and evaluated 3-hydroxy-3-ethynylindolin-2-one derivatives for in vitro cytotoxic activity. METHOD: An expeditious method for direct alkynylation of isatins (ketones) has been developed using tetrabutylammonium fluoride (TBAF) as a catalyst in THF solvent at room temperature under metal-free conditions. Furthermore, this method is an economically viable process that also compliments green aspects like being a ligand/metal free process under ambient conditions. This reaction tolerated a wide range of substrates with good to excellent yields (80-94%). RESULTS: The results showed that the synthesized compounds (4m, 4n and 4p) has the ability to inhibit Akt kinase activity with IC50 values ranging from 7.7 to 9.8 µM. CONCLUSION: All the 3-hydroxy-3-ethynylindolin-2-one derivatives were subjected for in vitro cytotoxic activity on five different cancer cell lines. Further, the synthesized compounds (4m, 4n and 4p) were evaluated for their ability to inhibit Akt kinase activity and exhibited good inhibition with IC50 values ranging from 7.7 to 9.8 µM..
Assuntos
Antineoplásicos/farmacologia , Citotoxinas/farmacologia , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citotoxinas/síntese química , Citotoxinas/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/síntese química , Indóis/química , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-akt/metabolismo , Relação Estrutura-AtividadeRESUMO
An optimized protocol was developed for shotgun proteomics of tomato fruit, which is a recalcitrant tissue due to a high percentage of sugars and secondary metabolites. A number of protein extraction and fractionation techniques were examined for optimal protein extraction from tomato fruits followed by peptide separation on nanoLCMS. Of all evaluated extraction agents, buffer saturated phenol was the most efficient. In-gel digestion [SDS-PAGE followed by separation on LCMS (GeLCMS)] of phenol-extracted sample yielded a maximal number of proteins. For in-solution digested samples, fractionation by strong anion exchange chromatography (SAX) also gave similar high proteome coverage. For shotgun proteomic profiling, optimization of mass spectrometry parameters such as automatic gain control targets (5E+05 for MS, 1E+04 for MS/MS); ion injection times (500 ms for MS, 100 ms for MS/MS); resolution of 30,000; signal threshold of 500; top N-value of 20 and fragmentation by collision-induced dissociation yielded the highest number of proteins. Validation of the above protocol in two tomato cultivars demonstrated its reproducibility, consistency, and robustness with a CV of < 10%. The protocol facilitated the detection of five-fold higher number of proteins compared to published reports in tomato fruits. The protocol outlined would be useful for high-throughput proteome analysis from tomato fruits and can be applied to other recalcitrant tissues.
RESUMO
Metal organic frameworks (MOFs) are a rapidly growing class of porous materials and are considered as best adsorbents for their high surface area and extraordinary porosity. The MOFs are synthesized by using various chemicals like triethylamine, terepthalic acid, zinc acetate dihydrate, chloroform, and dimethylformamide (DMF). Synthesized MOFs are intercalated with palladium/activated carbon, carbon black, and carbon nanomaterials by chemical reduction method for the purpose of enhancing the hydrogen adsorption capacities. We have observed that the palladium doped activated carbon on MOF-5 showed high hydrogen storage capacity. This may be due to the affinity of the palladium toward hydrogen molecule. The samples are characterized by X-ray diffraction, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. We have observed a clear decrease in the BET surface area and pore volume. The obtained results show a better performance for the synthesized sample. To our best knowledge, no one has reported the work on palladium-doped carbon materials (activated carbon, carbon black, carbon nanomaterials) impregnated to the metal-organic framework-5. We have attempted to synthesize carbon nanomaterials using indigenously fabricated chemical vapor deposition (CVD) unit as a support. We have observed an increase in the hydrogen storage capacities.
Assuntos
Carbono/química , Poluentes Ambientais/química , Compostos Organometálicos/análise , Paládio/química , Adsorção , Carvão Vegetal , Gases/química , Hidrogênio/química , Nanoestruturas/química , Porosidade , Difração de Raios XRESUMO
This paper reports on recycling of industrial wastes (three pharmaceutical industrial sludges) into environmental friendly value-added materials. Stabilization/Solidification (S/S or bricks) process was applied to make a safer way for the utilization of pharmaceutical waste. The additives in this study include binders (cement, lime and bentonite) and strengthening material (pulverized fuel ash (PFA), silica fume and quarry dust) was used at different compositions. Bricks were cured for 28 days, and the following analysis-like compressive strength, leachability of heavy metals, mineralogical phase identity by X-ray diffraction (XRD) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermal behaviour by thermogravimetric-differential thermal analysis (TG-DTA) had done. All the bricks were observed to achieve the standard compressive strength as required for construction according to BIS standards. Metal concentration in the leachate has reached the dischargeable limits according to Brazilian standards. Results of this study demonstrate that production of bricks is a promising and achievable productive use of pharmaceutical sludge.
Assuntos
Resíduos Industriais , Força Compressiva , Materiais de Construção/análise , Indústria Farmacêutica , Metais Pesados/química , Reciclagem/métodos , Esgotos , Difração de Raios XRESUMO
Hydrogen is an energy carrier of the future need. It could be produced from different sources and used for power generation or as a transport fuel which mainly in association with fuel cells. The primary challenge for hydrogen production is reducing the cost of production technologies to make the resulting hydrogen cost competitive with conventional fuels. Thermocatalytic decomposition (TCD) of methane is one of the most advantageous processes, which will meet the future demand, hence an attractive route for COx free environment. The present study deals with the production of hydrogen with 30 wt% of Ni impregnated in commercially available activated carbon and carbon black catalysts (samples coded as Ni30/AC and Ni30/CB, respectively). These combined catalysts were not attempted by previous studies. Pure form of hydrogen is produced at 850 °C and volume hourly space velocity (VHSV) of 1.62 L/h g on the activity of both the catalysts. The analysis (X-ray diffraction (XRD)) of the catalysts reveals moderately crystalline peaks of Ni, which might be responsible for the increase in catalytic life along with formation of carbon fibers. The activity of carbon black is sustainable for a longer time compared to that of activated carbon which has been confirmed by life time studies (850 °C and 54 sccm of methane).
Assuntos
Carbono/química , Hidrogênio/química , Metano/química , Catálise , Temperatura , Difração de Raios XRESUMO
In the present paper, the performance of electrocoagulation (EC) for the treatability of mixed metals (chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn)) from metal plating industrial wastewater (EPW) has been investigated. The study mainly focused on the affecting parameters of EC process, such as electrode material, initial pH, distance between electrodes, electrode size, and applied voltage. The pH 8 is observed to be the best for metal removal. Fe-Fe electrode pair with 1-cm inter-electrode distance and electrode surface area of 40 cm(2) at an applied voltage of 8 V is observed to more efficient in the metal removal. Experiments have shown that the maximum removal percentage of the metals like Cr, Ni, Zn, Cu, and Pb are reported to be 96.2, 96.4, 99.9, 98, and 99.5 %, respectively, at a reaction time of 30 min. Under optimum conditions, the energy consumption is observed to be 51.40 kWh/m(3). The method is observed to be very effective in the removal of metals from electroplating effluent.
Assuntos
Técnicas Eletroquímicas/métodos , Resíduos Industriais/prevenção & controle , Metais Pesados/isolamento & purificação , Águas Residuárias/química , Purificação da Água/métodos , Cromo/isolamento & purificação , Cobre/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Galvanoplastia , Concentração de Íons de Hidrogênio , Chumbo/isolamento & purificação , Níquel/isolamento & purificação , Purificação da Água/instrumentação , Zinco/isolamento & purificaçãoRESUMO
Uranium is a naturally occurring element, which is widespread in nature. It is found in low levels within all rocks, soils and water. Peddagattu and Seripally areas of Nalgonda district, Andhra Pradesh, India were known as a rich uranium mineralised zone. Atomic mineral division and Baba Atomic Research Center proposed a uranium mine in this area. This study was carried out to know the distribution of uranium concentration in the groundwater samples by using laser fluorimetry. The observation reveals that the uranium concentration in the groundwater of this region ranges from 0.6 to 521.15 ppb. About 43 % of the groundwater samples had the uranium concentration above the standards set by United States Environmental Protection Agency (30 ppb).
Assuntos
Fluorometria/métodos , Água Subterrânea/análise , Urânio/análise , Água Potável , Monitoramento Ambiental/métodos , Geografia , Índia , Monitoramento de Radiação/métodos , Poluentes Químicos da Água/análise , Poluentes Radioativos da Água/análise , Abastecimento de ÁguaRESUMO
In this study, we have evaluated the pulmonary toxicity of intratracheally (i.t.) instilled two multi walled carbon nanotubes (MWCNT) in rats. The lungs of rats were instilled with phosphate buffered saline + 1% of Tween 80 or MWCNT or carbonyl iron or quartz particles at a dose of 0.2, 1, and 5 mg/kg b.w. Following exposure, bronchoalveolar lavage (BAL) fluid was collected from the lungs to analyze lactate dehydrogenase (LDH), alkaline phosphatase (ALP), lipid peroxidation products (MDA; malondialdehyde), and total microprotein (MTP) levels at 24 h, one week, one month, and three months post instillation periods. The lungs of particle exposed rats were also collected at the same intervals to evaluate for histopathology. Exposures of MWCNT and quartz particles to rats produced transient dose dependant increase in BAL fluid LDH, ALP, MDA, and MTP values than control at all post exposure periods. Results of lung histopathology revealed that exposure of MWCNT produced a dose dependant focal peribronchiolar lymphoid aggregates, foamy alveolar macrophage accumulation, lymphoplasmocytic infiltration, fibrosis and diffuse alveolar damage. In conclusion, instillation of MWCNT produced a greater pulmonary toxicity in rats and was comparable with that of quartz.
Assuntos
Pulmão/efeitos dos fármacos , Pulmão/patologia , Nanotubos de Carbono/efeitos adversos , Animais , Líquido da Lavagem Broncoalveolar/química , Pulmão/enzimologia , Lesão Pulmonar/induzido quimicamente , Masculino , Nanotubos de Carbono/ultraestrutura , Pneumonia/induzido quimicamente , Quartzo/toxicidade , Ratos , Ratos WistarRESUMO
The aim of the present study was to evaluate the oxidative stress and anti-oxidant status in rat serum following intra-tracheal instillation of multi wall carbon nanotubes (MWCNT). The lungs of rats were intra-tracheally instilled with (single dose of) Phosphate-buffered saline (PBS)+1% of Tween 80 (Solvent Control) or MWCNT or carbonyl Iron (negative control) or quartz particles (positive control) at a dose of 0.2, 1 and 5 mg/kg body weight. Following exposure, the blood samples were collected at 1, 7, 30 and 90 days of post instillation of nanoparticles and different parameters were estimated to assess the oxidative stress induced by the instillation of MWCNT. Exposure of MWCNT to rats produced a significant (p<0.05) dose dependent reduction of blood total anti-oxidant capacity, glutathione, superoxide dismutase, catalase activity and increased lipid peroxidation product, (Malondialdehyde) levels than PBS+1% Tween 80 control group. This reduction in the total anti-oxidant capacity in nanotubes exposed rats indicates the reduction in anti-oxidant deference mechanisms due to the instillation of MWCNT. These results indicate that, exposure of multi wall carbon nanotubes induces oxidative stress by reducing the total anti-oxidant capacity in rats. The findings suggest possible occupational health hazard in chronic exposures.
Assuntos
Antioxidantes/metabolismo , Nanotubos de Carbono/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Animais , Catalase/metabolismo , Glutationa/metabolismo , Exposição por Inalação/efeitos adversos , Peroxidação de Lipídeos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar , Superóxido Dismutase/sangueRESUMO
In this study, we investigated the mechanisms involved in multi-wall carbon particles/nanomaterials (MWCNM) induced cytotoxicity using human embryonic kidney (HEK293) cells and to assess the effect of physicochemical properties on the cytotoxicity and oxidative stress induced by the carbon nanomaterials (CNM). To elucidate the possible mechanisms of CNM-induced cytotoxicity, cell viability (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide [MTT assay]), cell membrane damage (lactate dehydrogenase enzyme [LDH] assay), reduced glutathione (GSH), interleukin-8 (IL-8) and lipid peroxidation levels were quantitatively assessed under carbon nanomaterials exposed (48 h) conditions. Exposure of different sizes of four CNM at dosage levels between 3 and 300 µg/mL decreased cell viability in a concentration- and size-dependent manner. Exposure of CNM (10-100 µg/mL) to HEK cells resulted in size-, surface area- and concentration-dependent cell membrane damage, increased production of IL-8, increased thiobarbituric acid reactive substances (TBARS) and decreased intracellular glutathione levels. In summary, the physical properties of carbon nanoparticles may alter the CNM-induced concentration-dependent cytotoxicity and oxidative stress.
Assuntos
Sobrevivência Celular , Nanopartículas/toxicidade , Nanotubos de Carbono/toxicidade , Estresse Oxidativo , Tamanho da Partícula , Glutationa/análise , Células HEK293 , Humanos , Interleucina-8/análise , L-Lactato Desidrogenase/análise , Peroxidação de Lipídeos , Substâncias Reativas com Ácido Tiobarbitúrico/análiseRESUMO
This study evaluated the ability of the multi wall carbon nanotubes (MWCNT) to induce extra pulmonary toxicities in rats following intra-tracheal (IT) instillation of two MWCNT. Two carbon nanoparticles were instilled into the lungs of rats (0.2, 1, and 5 mg/kg b.w.) and at different post-exposure intervals, blood and organs like liver, kidney, etc. were collected. The histopathological examination of liver tissues revealed a dose-dependent periportal lymphocytic infiltration, ballooning, foamy degeneration, and necrosis at all post-instillation periods. However, examination of kidney revealed the tubular necrosis and interstitial nephritis with 5 mg/kg dose at 1 month of post-instillation of both MWCNT. These liver and kidney toxicities were further confirmed by the elevated levels of respective tissue damage biomarkers. These results suggest the extra pulmonary toxicities of these carbon nanoparticles might be due to the translocation into the liver and kidney.
Assuntos
Pulmão/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Animais , Creatinina/sangue , Relação Dose-Resposta a Droga , Coração/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Nanotubos de Carbono/ultraestrutura , Ratos , Ratos WistarRESUMO
The degradation of 2chloro-5methyl phenol (2C-5MP) in aqueous solution by ultrasonication (US) in the presence of TiO(2) and H(2)O(2) has been studied. Maximum degradation rate of 2.66 x 10(-2) was achieved by US/TiO(2)/H(2)O(2) process when compared to US/TiO(2) (1.01 x 10(-2)) and US/H(2)O(2) (5.5 x 10(-3)) systems. The effect of inorganic ions on degradation rate of 2C-5 MP were found to be in the order of Cl(-)>SO(4)(2-)>HPO(4)(2-)>HCO(3)(-). Further, the impact of synthetic additives like CCl(4) as hydrogen radical scavenger and CH(3)OH as hydroxyl radical scavenger on US were studied which confirmed the involvement of hydroxyl radicals in the degradation of 2C-5 MP. Kinetic studies revealed that the degradation process followed pseudo-first-order mechanism with the correlation coefficient (R(2)) of 0.9913 under experimental conditions.
Assuntos
Clorofenóis/química , Peróxido de Hidrogênio/química , Titânio/química , Concentração de Íons de Hidrogênio , Cinética , TemperaturaRESUMO
The hybrid up flow anaerobic sludge blanket reactor was evaluated for efficacy in reduction of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of bulk drug pharmaceutical wastewater under different operational conditions. The start-up of the reactor feed came entirely with glucose, applied at an organic loading rate (OLR) 1 kg COD/m(3) d. Then the reactor was studied at different OLRs ranging from 2 to 11 kg COD/m(3)d with pharmaceutical wastewater. The optimum OLR was found to be 9 kg COD/m(3)d, where we found 65-75% COD and 80-94% of BOD reduction with biogas production containing 60-70% of methane and specific methanogenic activity was 320 ml CH(4)/g-VSS d. By the characterization studies of effluent using GC-MS, the hazardous compounds like phenol, l,2-methoxy phenol, 2,4,6-trichloro phenol, dibutyl phthalate, 1-bromo naphthalene, carbamazepine and antipyrine were present. After the treatment, these compounds degraded almost completely except carbamazepine. Thermophilic methanothrix and methanosaetae like bacteria are present in the granular sludge.
Assuntos
Bactérias Anaeróbias/metabolismo , Reatores Biológicos , Indústria Farmacêutica , Resíduos Industriais , Purificação da Água/métodos , Biodegradação Ambiental , Reatores Biológicos/economia , Custos e Análise de Custo , Methanosarcinales/metabolismo , Oxigênio/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Purificação da Água/economiaRESUMO
This Study describes the feasibility of anaerobic degradation of United States Environmental Protection Agency (USEPA) listed 4-chloro-2-nitrophenol (4C-2-NP), 2-chloro-4-nitrophenol (2C-4-NP), 2-chloro-5-methylphenol (2C-5-MP) from a simulated wastewater using four identical 7L bench scale hybrid up flow anaerobic sludge blankets (HUASBs) at five different hydraulic retention times (HRTs) under thermophilic condition (55+/-3 degrees C). The substrate to co-substrate ratios were maintained between 1:33.3 and 1:166.6. Continuous monitoring of parameters like pH, volatile fatty acids (VFAs) accumulation, oxidation reduction potential, chemical oxygen demand (COD), alkalinity, gas productions, methane percentages were carried out along with compound reduction to asses the efficiency of biodegradation. The compound reduction was estimated by using spectrophotometric methods and further validated with high-performance liquid chromatography (HPLC). Optimum HRT values were observed at 24h. Optimum ratio of substrate (phenolic compounds) to co-substrate (glucose) was 1:100. Scanning electron micrographs show that the granules were composed of thermophilic Methanobrevibacter and thermophilic Methanothrix like bacteria.
Assuntos
Biodegradação Ambiental , Nitrofenóis/metabolismo , Esgotos/microbiologia , Anaerobiose , Reatores Biológicos/microbiologia , Laboratórios , Methanobrevibacter/crescimento & desenvolvimento , Methanobrevibacter/metabolismo , Methanosarcinaceae/crescimento & desenvolvimento , Methanosarcinaceae/metabolismoRESUMO
Composting was applied as a bioremediation methodology for the reclamation of dredged sediments of Isnapur, Khazipally and Gandigudem lakes polluted with industrial wastes. The present study is an attempt to elaborate upon organic matter transformations and define the parameters for product maturity adapting chemical and spectroscopic methods during composting. The stability and maturity of sediments were evaluated by assessing parameters like C/N ratio, nitrification index (NH(4)-N/NO(3)-N), water-soluble organic carbon concentration, CO(2) evolution rate, cation exchange capacity and indices such as humification index, E4/E6 ratio, compost mineralization index (ash content/oxidizable carbon), germination index, dehydrogenase, polyphenoloxidase activities and FTIR spectroscopy. The results showed that the changes in the above chemical and biological parameters can be employed as reliable indicators of stability and maturity. The FTIR spectra revealed enrichment in the aromatic groups and a degradation of the aliphatic groups indicating stabilization of the final compost.
Assuntos
Biodegradação Ambiental , Sedimentos Geológicos/análise , Resíduos Industriais/análise , Poluentes do Solo/análise , Solo/análise , Benzopiranos/análise , Carbono/análise , Dióxido de Carbono/metabolismo , Catecol Oxidase/metabolismo , Água Doce/análise , Germinação , Substâncias Húmicas/análise , Índia , Esterco , Nitratos/análise , Oxirredutases/metabolismo , Compostos de Amônio Quaternário/análise , Sementes/crescimento & desenvolvimento , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
In the present study an attempt is made efficiently to degrade USEPA listed 4-chloro-2-nitrophenol (4C-2-NP), widely available in bulk drug and pesticide wastes using various advanced oxidation processes (AOPs). A comparative assessment using various AOPs (UV, H(2)O(2,) UV/H(2)O(2), Fenton, UV/Fenton and UV/TiO(2)) was attempted after initial optimization studies, viz., varying pH, peroxide concentration, iron concentration, and TiO(2) loading. The degradation of the study compound was estimated using chemical oxygen demand (COD) reduction and compound reduction using spectrophotometric methods and further validated with high performance liquid chromatography (HPLC). The degradation trends followed the order: UV/Fenton > UV/TiO(2) > UV/H(2)O(2) > Fenton > H(2)O(2) > UV(.) It can be inferred from the studies that UV/Fenton was the most effective in partial mineralization of 4C-2-NP. However, lower costs were obtained with H(2)O(2). Kinetic constants were evaluated using first order equations to determine the rate constant K.
Assuntos
Nitrofenóis/análise , Oxigênio/química , Purificação da Água/métodos , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Ferro/química , Cinética , Nitrofenóis/química , Oxidantes Fotoquímicos , Oxirredução , Peróxidos/química , Espectrofotometria/métodos , Titânio/química , Raios UltravioletaRESUMO
During the process development of dutasteride in the laboratory analysis showed some impurity peaks in HPLC ranging from 0.05 to 0.1%. The same samples were analyzed by LCMS method and identified peak at m/z 508 (desmethyl dutasteride), 530 (dihydro dutasteride) and 528 (isomer of dutasteride). These impurities were synthesized individually and characterized based on the spectroscopic data (HPLC, IR, NMR and MS). The structures of these impurities were 17beta-N-[2,5-bis(trifluoromethyl) phenyl]carbamoyl-3-hydroxyl-4-azaestra-1,3,5,7,9-pentaene (desmethyl of dutasteride 2), 17beta-N-[2,5-bis(trifluoromethyl)phenyl]carbamoyl-4-aza-5alpha-androstane-3-one (dihydro impurity of dutasteride 3), and 17beta-N-[2,5-bis(trifluoromethyl) phenyl] carbamoyl-4-aza-5beta-androst-1-ene-3-one (beta-isomer of dutasteride 4), respectively. The formation and synthesis of dutasteride impurities are discussed.