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1.
RSC Adv ; 13(51): 36242-36253, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38090063

RESUMO

Herein, the efficacy of WOx-promoted CeO2-SiO2 and CeO2-ZrO2 mixed oxide catalysts in the solvent-free selective oxidation of benzyl alcohol to benzaldehyde using molecular oxygen as an oxidant is reported. We evaluated the effects of the oxidant and catalyst concentration, reaction duration, and temperature on the reaction with an aim to optimize the reaction conditions. The as-prepared CeO2, CeO2-ZrO2, CeO2-SiO2, WOx/CeO2, WOx/CeO2-ZrO2, and WOx/CeO2-SiO2 catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, Raman spectroscopy, temperature-programmed desorption of ammonia (TPD-NH3), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). These characterisation results indicated that the WOx/CeO2-SiO2 catalyst possessed improved physicochemical (i.e., structural, textural, and acidic) properties owing to the strong interactivity between WOx and CeO2-SiO2. A higher number of Ce3+ ions (Iu'''/ITotal) were created with the WOx/CeO2-SiO2 catalyst than those with the other catalysts in this work, indicating the generation of a high number of oxygen vacancies. The WOx/CeO2-SiO2 catalyst exhibited a high conversion of benzyl alcohol (>99%) and a high selectivity (100%) toward benzaldehyde compared to the other promoted catalysts (i.e., WOx/CeO2 and WOx/CeO2-ZrO2), which is attributed to the smaller particle size of the WOx and CeO2 and their high specific surface area, more significant number of acidic sites, and superior number of oxygen vacancies. The WOx/CeO2-SiO2 catalyst could be quickly recovered and utilized at least five times without suffering any appreciable activity loss.

2.
Environ Pollut ; 335: 122270, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37516292

RESUMO

Estimation of community-wide consumption of illicit drugs through wastewater analysis is a new concept in Africa although widely applied in developed nations as wastewater-based epidemiology (WBE). It is an important tool that can be used in understanding supply and demand patterns of illicit drug use on a local, national, and international scale. Information on illicit drug use is currently limited in Africa, because of a lack of monitoring structures by governments and financial constraints. This study hopes to bridge that gap by contributing to Africa's baseline information on illicit drug use. This study provides the first application of wastewater analysis to quantitatively evaluate daily illicit drug use in the eThekwini Metropolitan Municipality of KwaZulu-Natal Province of South Africa by quantifying the major urinary excreted metabolites, called drug target residues (DTRs), in raw wastewater from four major wastewater treatment plants (WWTPs) sampled for a week. The results showed that cocaine was the dominant illicit drug consumed in the catchment followed by amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine, with a per capita use of 360-3000 mg day-1 1000 inh-1, 47-800 mg day-1 1000 inh-1, 19-120 mg day -1 1000 inh-1, not detected (ND) to 4.9 mg day-1 1000 inh-1, and ND to 410 g day-1 1000 inh-1 respectively. The weekly usage patterns between the four WWTPs differed probably due to the lifestyle of the populace serving the different WWTPs. These results provide useful data on illicit drug use in eThekwini that can be utilised by public health agencies to implement suitable response strategies.


Assuntos
Drogas Ilícitas , Transtornos Relacionados ao Uso de Substâncias , Poluentes Químicos da Água , Humanos , Águas Residuárias , África do Sul , Detecção do Abuso de Substâncias/métodos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Anfetamina , Poluentes Químicos da Água/análise
3.
Heliyon ; 9(2): e13514, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36846710

RESUMO

Synthesis and catalytic studies of aryl carboxylate Zn (II) complexes is reported. Reaction of substituted (E)-N-phenyl-1-(pyridin-4-yl)methanimine with a methanolic solution of Zn(CH3COO)2 and substituted aryl carboxylate co-ligands gave heteroleptic Zn(II) complexes; [Zn(C6H5COO)2(L1)]2 (1), [Zn(C7H7COO)2(L1)]2 (2), [Zn (4-F-C6H4COO)2(L1)]2 (3), [Zn(C6H5COO)2(L2)]2 (4), [Zn(C7H7COO)2(L2)]2 (5), [Zn (4-F-C6H4COO)2(L2)]2 (6), [Zn(C6H5COO)2(L3)]2 (7), [Zn(C7H7COO)2(L3)]2 (8), [Zn (4-F-C6H4COO)2(L3)]2 (9). The molecular structures of complexes 1 and 4 are dinuclear with the zinc atom in complex 1 adopting a distorted trigonal bipyramidal geometry in a bi-metallacycle while complex 4 is square pyramidal where all four benzoate ligands bridge the zinc metals in a paddle wheel arrangement. All complexes successfully initiated mass/bulk ring-opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) and lactides (LAs) monomers with or without alcohol co-initiators at elevated temperatures. Complexes 1, 4 and 6 containing the unsubstituted benzoate co-ligands were the most active in their triad; with complex 4 being the most active (k app) of 0.3450 h-1. The physicochemical properties of the polymerization products of l-lactide and rac-lactide in toluene revealed melting temperatures (Tm) between 116.58 °C and 188.03 °C, and decomposition temperatures between 278.78 °C and 331.32 °C suggestive of an isotactic PLA with a metal capped end.

4.
RSC Adv ; 12(22): 14282-14298, 2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35702657

RESUMO

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal-organic frameworks (MOFs), with unique physical, chemical and mechanical properties. MOF-5 based composites possess ample applications in modern chemistry. Huge surface area, suitable pore dimensions and scope of tunability make MOF-5 noteworthy in advanced materials. The extensive features of MOF-5 provided an opportunity for researchers to explore atomic/molecular scale materials. Various MOF-5 based composites have been designed with revamped properties appropriate to the application by altering and fabricating MOF-5 in situ or using a post-synthetic approach. Surface modification via the dispersion and impregnation of active substances into the pores of MOF-5 enhances its applicability. The boundless topologies and morphologies of MOF-5 combined with other chemical entities has provided opportunities in various fields, including catalysis, gas storage and sensors. The present review illuminates the leading role of MOF-5 and its composites in contemporary applications based on the current literature in heterogeneous catalysis, H2 and CO2 storage and sensors.

5.
Molecules ; 26(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071629

RESUMO

Heterogeneous catalysis plays a crucial role in many chemical processes, including advanced organic preparations and the design and synthesis of new organic moieties. Efficient and sustainable catalysts are vital to ecological and fiscal viability. This is why green multicomponent reaction (MCR) approaches have gained prominence. Owing to a broad range of pharmacological applications, pyranopyrazole syntheses (through the one-pot strategy, employing sustainable heterogeneous catalysts) have received immense attention. This review aimed to emphasise recent developments in synthesising nitrogen-based fused heterocyclic ring frameworks, exploring diverse recyclable catalysts. The article focused on the synthetic protocols used between 2010 and 2020 using different single, bi- and tri-metallic materials and nanocomposites as reusable catalysts. This review designated the catalysts' efficacy and activity in product yields, reaction time, and reusability. The MCR green methodologies (in conjunction with recyclable catalyst materials) proved eco-friendly and ideal, with a broad scope that could feasibly lead to advancements in organic synthesis.

6.
Front Chem ; 9: 638832, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33869142

RESUMO

We report a highly efficient green protocol for developing a novel library of 1,2,4-triazole-tagged 1,4-dihydropyridine analogs through the one-pot process from the four-component fusion of the 1H-1,2,4-triazol-3-amine with different chosen aldehydes, diethyl acetylenedicarboxylate, and active methylene compounds in a water medium under microwave irradiation and catalyst-free conditions. Excellent yields (94-97%) of the target products were achieved with high selectivity with a short reaction time (<12 min) at room temperature. The structures of the synthesized pyrimidine analogs were established by NMR and HRMS spectroscopic analysis. Simple workup, impressive yields, no column chromatography, green solvent, rapid reaction, and excellent functional group tolerance are the benefits of this protocol.

7.
Curr Drug Discov Technol ; 18(6): e130921187682, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33155923

RESUMO

BACKGROUND & OBJECTIVE: A facile and efficient method for the synthesis of novel derivatives of FQ citrate conjugates with 1,2,4-triazoles and 1,3,4-oxadiazole scaffolds 8-11 using conventional, as well as microwave irradiation methods, was reported. Based on these original building blocks, the new derivatives of 3, 7-disubstituted fluoroquinolones bearing the oxadiazolyl-triazole groups were obtained. These invaluable derivatives are of great interest in medicinal and pharmaceutical studies because of their important biological properties. METHODS: All the reactions were examined under conventional as well as microwave mediated conditions. The structures of obtained compounds were confirmed by 1H NMR, 13C NMR, IR HRMS spectroscopy, and elemental analysis. The antibacterial and antifungal activities of these compounds were screened against Gram-positive, Gram-negative bacteria, and fungal stains by the agar well diffusion method. Cytotoxic assay of the title compounds was evaluated against cervical carcinoma cell line (HeLa) by using the MTT assay. The crystal structure of the Quinolone-DNA cleavage complex of type IV topoisomerase from S. pneumoniae (PDB ID: 3RAE) complex was obtained from the Protein Database (PDB, http:// www.rcsb.org). Molecular properties prediction-drug likeness was studied by Molinspiration and Molsoft software, while lipophilicity and solubility parameters were studied using the Osiris program. RESULTS: A novel approach for the synthesis of benzylthio-1,2,4-triazole and 1,3,4-oxadiazoles core with regioisomeric norfloxacin citrate conjugates was developed. Among the title compounds, 11b, 10a reveal pronounced activity against S. pneumoniae with minimum inhibitory concentrations of 0.89, 0.96 mg/mL and MBCs of 2.95, 2.80 mg/mL, respectively. Minimum Fungicidal Concentration (MFC) has been determined for each compound against two fungal strains. Compound 11b showed maximum anti-cancer activity against HeLa cell line with IC50 value 11.3 ± 0.41 comparable to standard drug DXN. For binding mode, active site residues and docking energies (ΔG =-7.9 Kcal/mol) for ligand 9b exhibited the highest hydrogen bonding (3.59274 A˚), Pi- Alkyl (5.14468 A˚) interactions with amino acid LEU479 of 3RAE protein. The compounds following the Lipinski 'Rule of five' were synthesized for antimicrobial and anti-cancer screening as oral bioavailable drugs/leads. Maximum drug likeness model score 1.52, 1.41 was found for compounds 10d, 11b. CONCLUSION: The present work, through simple synthetic approaches, led to the development of novel hybrids of fluoroquinolone containing citrate-triazole-oxadiazole pharmacophores that exhibited remarkable biological activities against different microorganisms and cell lines. The compounds showed suitable druglike properties and are expected to present good bioavailability profile. An efficient combination of molecular modeling and biological activity provided an insight into QSAR guidelines that could aid in further development and optimization of the norfloxacin derivatives.


Assuntos
DNA Topoisomerase IV , Fluoroquinolonas , Ácido Cítrico , DNA Topoisomerase IV/metabolismo , Fluoroquinolonas/farmacologia , Células HeLa , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade
8.
Front Chem ; 9: 747615, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34976945

RESUMO

Metal-organic frameworks (MOFs) have emerged as versatile candidates of interest in heterogeneous catalysis. Recent research and developments with MOFs positively endorse their role as catalysts in generating invaluable organic compounds. To harness the full potential of MOFs in value-added organic transformation, a comprehensive look at how these materials are likely to involve in the catalytic processes is essential. Mainstays of MOFs such as metal nodes, linkers, encapsulation materials, and enveloped structures tend to produce capable catalytic active sites that offer solutions to reduce human efforts in developing new organic reactions. The main advantages of choosing MOFs as reusable catalysts are the flexible and robust skeleton, regular porosity, high pore volume, and accessible synthesis accompanied with cost-effectiveness. As hosts for active metals, sole MOFs, modified MOFs, and MOFs have made remarkable advances as solid catalysts. The extensive exploration of the MOFs possibly led to their fast adoption in fabricating new biological molecules such as pyridines, quinolines, quinazolinones, imines, and their derivatives. This review covers the varied MOFs and their catalytic properties in facilitating the selective formation of the product organic moieties and interprets MOF's property responsible for their elegant performance.

9.
Front Chem ; 9: 800236, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34993177

RESUMO

The synthesis of dihydropyridines, valuable molecules with diverse therapeutic properties, using eco-friendly heterogeneous catalysts as a green alternative received significant consideration. By selecting appropriate precursors, these compounds can be readily modified to induce the desired properties in the target product. This review focused on synthesising diverse dihydropyridine derivatives in single-pot reactions using magnetic, silica, and zirconium-based heterogeneous catalytic systems. The monograph describes preparation techniques for various catalyst materials in detail. It covers facile and benign magnetic, silica, zirconium-based, and ionic liquid catalysts, exhibiting significant efficacy and consistently facilitating excellent yields in short reaction times and in a cost-effective way. Most of the designated protocols employ Hantzsch reactions involving substituted aldehydes, active methylene compounds, and ammonium acetate. These reactions presumably follow Knoevenagel condensation followed by Michael addition and intra-molecular cyclisation. The multicomponent one-pot protocols using green catalysts and solvents have admirably increased the product selectivity and yields while minimising the reaction time. These sustainable catalyst materials retain their viability for several cycles reducing the expenditure are eco-friendly.

10.
J Tradit Complement Med ; 10(6): 586-593, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33134135

RESUMO

BACKGROUND AND AIM: Gastric ulcer is a chronic disease and serious health issue. Celosia trigyna is a medicinal plant used traditionally for wound healing. This study aimed to isolate the bioactive compounds from Celosia trigyna and to investigate the in vitro and in vivo anti-ulcerogenic effects of the extracts on ethanol-induced gastric ulcer on adult Wistar rats to determine their regenerative potential. EXPERIMENTAL PROCEDURE: Seven groups (A - negative control, B - vehicle control, C, D, E, F and G - positive control, n = 5) of five adult Wistar rats received treatment for ethanol-induced gastric ulcer. RESULTS AND CONCLUSION: Phytochemical analysis led to the isolation of chondrillasterol, lutein, pheophytin a and chondrillasterol acetate. The in vitro results showed dichloromethane and hexane extracts to have maximum chymotrypsin inhibition relative to the standard (chymostatin) while in vivo results showed a significant increase in ulcer parameters of the vehicle control relative to groups treated with plant extracts (P < 0.05). Ulcer parameters and DNA density in groups treated with dichloromethane and hexane extracts were comparable to the negative control. Gross and histopathological findings confirmed gastric mucosa lesions in the vehicle control. There were mild ulcerations in groups treated with the ethyl acetate and methanol extracts with no observable ulcerations in the groups treated with dichloromethane and hexane extracts as the histoarchitectural outlines do not show any form of necrosis, distortion or cellular vacuolation. It was concluded that non-polar, hydrophobic compounds are able to remediate the degree of ulceration but not polar compounds.

11.
Molecules ; 25(8)2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32326131

RESUMO

The analogs of nitrogen-based heterocycles occupy an exclusive position as a valuable source of therapeutic agents in medicinal chemistry. More than 75% of drugs approved by the FDA and currently available in the market are nitrogen-containing heterocyclic moieties. In the forthcoming decade, a much greater share of new nitrogen-based pharmaceuticals is anticipated. Many new nitrogen-based heterocycles have been designed. The number of novel N-heterocyclic moieties with significant physiological properties and promising applications in medicinal chemistry is ever-growing. In this review, we consolidate the recent advances on novel nitrogen-containing heterocycles and their distinct biological activities, reported over the past one year (2019 to early 2020). This review highlights the trends in the use of nitrogen-based moieties in drug design and the development of different potent and competent candidates against various diseases.


Assuntos
Compostos Heterocíclicos/química , Nitrogênio/química , Desenho de Fármacos , Desenvolvimento de Medicamentos , Compostos Heterocíclicos/farmacologia , Humanos , Estrutura Molecular , Relação Estrutura-Atividade
12.
Food Chem ; 319: 126596, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32199145

RESUMO

The collection of wild edible mushrooms for use is an ancient practice. In this study, the elemental concentrations in five mushrooms were compared as a function of species and geographical location. The accumulation of metals from the substrate was found to be species dependent. Mushrooms excluded As, Be, Ca, Cd, Co, Cr, Fe, Mn, Ni and Si, and accumulated elements in the following order: Amanita pantherina (K > Na > Zn > Cu > Mg); Boletus edulis (edible) (K > Cu > Zn > Se > Na > Mg); Boletus mirabilis (edible) (K > Cu > Zn > Na > Mg); Lactarius deliciosus (edible) (K > Zn > Mg); and Russula sardonia (K > Na > Zn > Cu > Mg). Statistical analysis showed soil parameters to affect elemental accumulation by edible mushrooms more than inedible ones, especially for uptake of Se by B. edulis, which was antagonistic with As and Pb in the soil. The results also showed the edible mushrooms to contain proteins (25 - 55%), carbohydrates (34 - 69%), ash (3-6.5%) and lipids (0.8-5.3%).


Assuntos
Agaricales/química , Metais/análise , Minerais/análise , Valor Nutritivo , Solo/química , Basidiomycota/química , Bioacumulação , Análise de Alimentos , África do Sul
13.
Biol Trace Elem Res ; 198(1): 303-314, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31960277

RESUMO

Edible fruits of two indigenous medicinal Ficus species (Ficus sycomorus L. and Ficus burtt-davyi Hutch) collected from eight different sites in South Africa were assessed for nutritional value, elemental concentration, and the possible risk associated with their consumption. The metal concentrations in the fruits and growth soil were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The results showed elemental concentrations in the fruits to contribute significantly to recommended dietary allowances and were found to be in decreasing order of Ca > Mg > Fe > Zn > Mn > Cu > Cr and Ca Ëƒ Mg Ëƒ Fe Ëƒ Mn Ëƒ Zn Ëƒ Cu for both F. sycomorus and F. burtt-davyi fruits. The results for proximate composition of F. sycomorus fruits were (in %) 55.8 for moisture, 25.3 for carbohydrates, 5.6 for protein, 8.9 for fats, 55.8 for crude fiber, and 4.4 for ash; for F. burtt-davyi fruits, it was (in %) 78.9 for carbohydrates, 5.0 for protein, 8.4 for lipids, 4.0 for crude fiber, and 3.7 for ash. The health risk assessment showed target hazard quotient, and hazard indices for all the studied heavy metals in the fruits for all the sites were to be less than one and the target carcinogenic risk values to be within the acceptable regulatory cancer risk range. This study confirms that the fruits of F. sycomorus and F. burtt-davyi are safe for human consumption due to low non-carcinogenic and carcinogenic adverse health effects.


Assuntos
Ficus , Metais Pesados , Poluentes do Solo , Monitoramento Ambiental , Frutas/química , Humanos , Metais Pesados/análise , Medição de Risco , Poluentes do Solo/análise , África do Sul
14.
J Environ Sci Health B ; 55(4): 396-405, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31905102

RESUMO

Bentazone is one of the toxic insecticides used to control forest tent caterpillar moths, boll weevils, gypsy moths, and other types of moths in various field crops. We report the efficacy of biochar prepared from the Azardirachta Indica waste biomass as adsorbent for removal of Bentazone. Biochar material was prepared by pyrolysis process under limited oxygen conditions. Biochar material was characterized by proximate and ultimate analysis, SEM analysis, FTIR analysis and TG/DTA analyses. The Bentazone adsorption capacity by biochar from aqueous solutions was assessed. Effect of time, adsorbent dosage, insecticide concentration and pH on the adsorption characteristics of the biochar were evaluated. Adsorption parameters were obtained at equilibrium contact time of 150 min, with biochar dosage of 0.5 g at pH 8. From the optimization studies, desirability of 0.952 was obtained with response (adsorption uptake) of 79.40 mg/g, for initial concentration of insecticide (50 mg/L), adsorbent dosage (0.448 g), time 30.0 min and pH 2. The adsorption isotherm data for the removal of Bentazone fitted well with the Freundlich isotherm. This study indicates that the biochar produced from the bark of Azardirachta Indica biomass could be employed as a potential adsorbent for removal of synthetic organic pollutants from the water streams.


Assuntos
Benzotiadiazinas/isolamento & purificação , Carvão Vegetal/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Azadirachta/química , Benzotiadiazinas/química , Biomassa , Concentração de Íons de Hidrogênio , Inseticidas/química , Inseticidas/isolamento & purificação , Cinética , Casca de Planta/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/química , Purificação da Água
15.
Mol Divers ; 24(4): 889-901, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31598820

RESUMO

Use of cheaper and recyclable materials contributes positively to economic growth with environmental sustainability. We report the prospect of utilizing red brick clay as catalyst, which exhibited excellent activity in rapid one-pot four-component condensation of 1,2,4,5-tetrasubstituted imidazoles with high conversion and yields (91-96%) in aqueous medium at 60 °C in short reaction times (25-40 min). The red brick clay material was fully characterized by XRD, FT-IR, SEM, TEM, EDX and BET analyses. Red brick clay consisted of oxides of Si (20.38%), Fe (19.55%), Al (14.30%) and minor amounts of Ca (3.60%) and Mg (1.68%). The slate-like-shaped structure morphology and flaky appearance of inexpensive solid clay material proved competent material for the synthesis of 15 novel 1,2,4,5-tetrasubstituted imidazole derivatives. In addition, the advantages of the eco-friendly method are non-toxicity and re-usability of the catalyst. Reaction offers 78% atom economy and 84% carbon capture.


Assuntos
Argila/química , Imidazóis/síntese química , Catálise/efeitos dos fármacos , Química Verde/métodos , Óxidos/química , Dióxido de Silício/química
16.
Mol Divers ; 24(2): 345-354, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31098860

RESUMO

The Bi2O3 loading on ZrO2 as heterogeneous catalyst was established as an extremely efficient catalyst for the synthesis of a series of novel 5-(1-(2,4-dinitrophenyl)-3-substituted-phenyl-1H-pyrazol-4-yl)-1,2,4-triazolidine-3-thione derivatives (3a-o) with high yields (90-96%) by reaction of 1-(2,4-dinitrophenyl)-3-substituted-phenyl-1H-pyrazole-4-carbaldehydes and thiosemicarbazide using water as a greener solvent at 80 °C within 30-45 min. Materials with different percentages of Bi2O3 on ZrO2 were prepared by simple wet impregnation method. The synthesized material has been characterized by various techniques (XRD, TEM, SEM, BET). 2.5% Bi2O3/ZrO2 proved superior catalyst. The Bi2O3/ZrO2 catalyst is easily recoverable and reused up to sixth run with no loss of activity. Excellent yields, short reaction time, avoidance of hazardous solvents, and no need for chromatographic purifications are the proven advantages.


Assuntos
Bismuto/química , Pirazóis/química , Tionas/química , Triazóis/química , Zircônio/química , Catálise , Reciclagem
17.
Biomed Chromatogr ; 34(1): e4719, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634417

RESUMO

A quality by design (QbD) based high-resolution HPLC method is described for determination of impurities in apixaban (APX) in the tablet dosage form. Employing a simple and stability-indicating HPLC method, nine known impurities were quantified with good peak resolution. Mobile phase A (MP-A) was prepared with buffer and acetonitrile 90:10 v/v, while mobile phase B (MP-B) contained water and acetonitrile 10:90 v/v. The gradient program was 0 min, MP-A 75%, B 25%; 20 min, MP-A 65%, B 35%; 30 min, MP-A 40%, B 60%; 40min, MP-A 40%, B 60%; 42 min, MP-A 75%, B 25%; and 50 min, MP-A 75%, B 25%. The chromatographic separation was achieved using a Zorbax RX C18 250 × 4.6 mm column, 5 µm (1.0 ml min-1 , 280 nm, 50 µl) and a column temperature of 40°C. Several separation studies were carried out using design of experiments to optimize the method. Validation results confirm the applicability of the developed method for quality analysis and stability studies of the regular product on the manufacturing stream.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Contaminação de Medicamentos , Pirazóis/análise , Pirazóis/química , Piridonas/análise , Piridonas/química , Estabilidade de Medicamentos , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Comprimidos
18.
RSC Adv ; 10(34): 19803-19810, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-35520453

RESUMO

We synthesised materials with different loadings of vanadia on fluorapatite (V2O5/FAp), fully characterised their structural properties using various spectral techniques including TEM, BET, XRD, FT-IR, SEM and EDX and assessed their prowess as catalysts. The 2.5% V2O5/FAp exhibited excellent activity for the synthesis of novel [1,3,4]thiadiazolo[3,2-a]pyrimidines and benzo[4,5]thiazolo[3,2-a]pyrimidines. The one-pot three-component fusion reaction between chosen substrates of 1,3,4-thiadiazole-amines or 2-amino-benzothiazole, aldehydes and active methylene compounds in ethanol solvent at room temperature gave an excellent yield of products (90-97%) in a swift reaction (25-30 min). The advantages of this protocol are rapid synthesis, mild reaction conditions, green solvent, easy work-up, eco-friendliness, reusability of catalyst and no need for column chromatography.

19.
J Environ Sci Health B ; 55(4): 406-415, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31880191

RESUMO

Carpobrotus dimidiatus is an indigenous South African medicinal plant species from the Aizoaceae family that bears edible fruit that is consumed for nutritional value. In this study, the elemental distribution in C. dimidiatus fruit and growth soil from fifteen sites in KwaZulu-Natal (South Africa) was determined along with soil pH, soil organic matter and cation exchange capacity, to assess for nutritional value and the effect of soil quality on elemental uptake. The results showed elemental concentrations in fruit to be in decreasing order of Ca (6235-32755 mg kg-1) > Mg (2250-5262 mg kg-1) > Fe > Mn > Zn (20.9-50.6 mg kg-1) > Cu (3.83-20.6 mg kg-1) > Pb > Cr > Cd > As ∼ Co ∼ Ni ∼ Se and no potential health risk due to metal toxicity from average consumption. For sites that had high levels of Cd and Pb, bioaccumulation occurred from atmospheric deposition. Concentrations of elements in soil were found to be in decreasing order of Fe (1059-63747 mg kg-1) > Ca (1048-41475 mg kg-1) > Mg > Mn (9.76-174 mg kg-1) > Cr (1.55-135 mg kg-1) > Zn (0.76-58.2 mg kg-1) > Se > Cu > Ni > Pb > Co > As ∼ Cd with no evidence of heavy metal contamination. This study revealed that the plant inherently controlled uptake of essential elements according to physiological needs and that the concentrations of essential elements in the fruit could contribute positively to the diet.


Assuntos
Aizoaceae/química , Frutas/química , Metais/análise , Solo/química , Oligoelementos/análise , Humanos , Valor Nutritivo , Poluentes do Solo/análise , África do Sul
20.
Chem Biodivers ; 17(1): e1900462, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31788939

RESUMO

A series of coumarin-tagged ß-lactam triazole hybrids (10a-10o) were synthesized and tested for their cytotoxic activity against MDA-MB-231 (triple negative breast cancer), MCF-7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK-293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF-7 cancer cell lines with IC50 values of 53.55 and 58.62 µm, respectively. More importantly, compounds 10b and 10d were non-cytotoxic against HEK-293 cell lines. Structure-activity relationship (SAR) studies suggested that the nitro and chloro group at the C-3 position of phenyl ring are favorable for anticancer activity, particularly against MCF-7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Cumarínicos/farmacologia , Triazóis/farmacologia , beta-Lactamas/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Proliferação de Células/efeitos dos fármacos , Cumarínicos/síntese química , Cumarínicos/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Células MCF-7 , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Relação Estrutura-Atividade , Triazóis/química , beta-Lactamas/química
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