RESUMEN
The need for green synthesis of emerging industrial materials has led to the biosynthesis of nanoparticles from plants to circumvent the adverse by-products of chemical synthesis. In this study, the leaf extract of Detarium mirocarpum Guill & Perr, a small tree belonging to the family Fabaceae (Legume), was used to synthesize silver nanoparticles (DAgNPs). DAgNPs were characterized using spectroscopic techniques (Ultraviolet-Visible spectroscopy and Fourier Transform Infrared spectroscopy) which showed hydroxyl and carbonyl functional groups to be responsible for their synthesis. DAgNPs were observed to be crystalline and spherical. The average size, determined by transmission electron microscopy (TEM) was 17.05nm. The antioxidant activity of DAgNPs ranked from moderate to good. The ability of DAgNPs to sense Hg(2+) and Fe(3+) ions in aqueous medium was also investigated. The quenching of the SPR peak at 430nm was used to monitor the toxic and heavy metal ions with linear ranges of 20-70µgmL(-1) and 10-40µgmL(-1) for Hg(2+) and Fe(3+), respectively. The limit of detection (LOD) and limit of quantification (LOQ) obtained for Hg(2+) was 2.05µgmL(-1) and 6.21µgmL(-1), respectively and for Fe(3+) was 5.01µgmL(-1) and 15.21µgmL(-1), respectively. The intra- and inter-day assessments of accuracy and repeatability gave relative errors less than 1% in all instances. DAgNPs can therefore provide a convenient method of sensing the toxic metals easily.
Asunto(s)
Fabaceae , Nanopartículas del Metal/química , Extractos Vegetales/química , Nitrato de Plata/química , Plata/química , Compuestos de Bifenilo/química , Colorimetría , Hierro/análisis , Hierro/química , Mercurio/análisis , Mercurio/química , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Óxido Nítrico/química , Oxidación-Reducción , Picratos/química , Hojas de la Planta/químicaRESUMEN
The monoazo dyes, 4-carboxyl-2, 6-dinitrophenylazohydroxynaphthalenes dyes (AZ-01, AZ-03 and AZ-04), were evaluated as a highly selective colorimetric chemosensor for cyanide ion. The recognition of cyanide ion gave an obvious colour change from light yellow to brownish red and upon dilution with acetone produced a purple to lilac colour. Optimum conditions for the reaction between the azo dyes and cyanide ion were established at 30°C for 5 min, and different variables affecting the reaction were carefully studied and optimised. Under the optimum conditions, linear relationships between the CN(-) concentrations and light absorption were established. Using these azo-hydrazone molecular switch entities, excellent selectivity towards the detection of CN(-) in aqueous solution over miscellaneous competitive anions was observed. Such selectivity mainly results from the possibility of nucleophilic attack on the azo-hydrazone chemosensors by cyanide anions in aqueous system, which is not afforded by other competing anions. The cyanide chemosensor method described here should have potential application as a new family probes for detecting cyanide in aqueous solution.
Asunto(s)
Compuestos Azo/química , Cianuros/análisis , Hidrazonas/química , Colorimetría/métodos , Estructura MolecularRESUMEN
OBJECTIVE: To evaluate the success rate of tuberculosis intervention programme at a specialist hospital in Ibadan, Nigeria through a retrospective study as well as carry out physicochemical evaluation of anti-tuberculous agents as a way of eliminating drug-related failure. METHODS: The retrospective study involved the use of quarterly tuberculosis central register at the Government Chest Hospital, Ibadan between 1st quarter (2003) to 4th quarter (2009). Relevant data were extracted from these register with the aid of data collection forms. The basic physicochemical analyses of the drugs given to the patients were also carried out using the International Pharmacopoeia methods. RESULTS: All the drugs examined for their physicochemical properties passed the International Pharmacopeia recommended tests. A total number of 1 260 patients enrolled at the hospital were assessed through case notes. This comprises of 59.4% males of which 69.23% new cases were also males. There was a significant (P<0.05) patient enrollment across the quarters for the seven years. An overall 80.24% cure rate over the 7-period was obtained which is less than the WHO target of 85%. Cure rates were better in females than males. Failure treatment outcomes such as positive (1.51%), deaths (8.73%), defaulted (3.33%) and transferred out (5.95%) were recorded though not statistically significant (P>0.05). Failure rates in all categories were higher in males than females (P>0.05). CONCLUSIONS: More enlightenment and counseling is still required to meet up with the target for TB control.
Asunto(s)
Antituberculosos/uso terapéutico , Terapia por Observación Directa/estadística & datos numéricos , Tuberculosis/tratamiento farmacológico , Antituberculosos/química , Femenino , Humanos , Masculino , Nigeria , Estudios Retrospectivos , Centros de Atención Secundaria , Resultado del Tratamiento , Tuberculosis/epidemiologíaRESUMEN
The intermolecular interaction occurring between bovine serum albumin and 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalene in aqueous media has been studied spectrophotometrically at different temperatures including body temperature. Evidence for the formation of new molecular complexes was established by hypsochromic and hypochromic shifts of the spectra of dye-BSA complexes compared to the spectra of unbound dyes. One congener (AZ-02) gave a minor peak characteristic of charge-transfer complexation. The binding constants of the four monoazo dyes were investigated and found to vary according to the dye structure and temperature of investigation. AZ-01 and -04 combined with BSA at approximately 1:1 mol ratio while the other two congeners with additional proton donors gave greater than this mole ratio. Thermodynamic considerations established that the dyes utilized the various forms of binding modes; hydrogen bonding, hydrophobic bonding, van der Waals and AZ-03 was particularly involved in electrostatic interactions giving positive entropy change for a small enthalpy change. The observed properties were correlated with the genotoxicity potentials of the monoazo dyes. The results obtained should prove beneficial in designing other molecules in this category of chemical class.
Asunto(s)
Naftalenos/metabolismo , Albúmina Sérica Bovina/metabolismo , Absorción/efectos de los fármacos , Animales , Bovinos , Colorantes/química , Colorantes/metabolismo , Colorantes/toxicidad , Electrones , Humanos , Cinética , Mutágenos/toxicidad , Naftalenos/química , Naftalenos/toxicidad , Unión Proteica/efectos de los fármacos , Espectrofotometría Ultravioleta , TermodinámicaRESUMEN
The study is a description of a sensitive spectrophotometric determination of aceclofenac following azo dye formation with 4-carboxyl-2,6-dinitrobenzenediazonium ion (CDNBD). Spot test and thin layer chromatography revealed the formation of a new compound distinct from CDNBD and aceclofenac. Optimization studies established a reaction time of 5 min at 30 degrees C after vortex mixing the drug/CDNBD for 10 s. An absorption maximum of 430 nm was selected as analytical wavelength. A linear response was observed over 1.2-4.8 µg/mL of aceclofenac with a correlation coefficient of 0.9983 and the drug combined with CDNBD at stoichiometric ratio of 2 : 1. The method has a limit of detection of 0.403 µg/mL, limit of quantitation of 1.22 µg/mL and is reproducible over a three day assessment. The method gave Sandell's sensitivity of 3.279 ng/cm2. Intra- and inter-day accuracies (in terms of errors) were less than 6% while precisions were of the order of 0.03-1.89% (RSD). The developed spectrophotometric method is of equivalent accuracy (p > 0.05) with British Pharmacopoeia, 2010 potentiometric method. It has the advantages of speed, simplicity, sensitivity and more affordable instrumentation and could found application as a rapid and sensitive analytical method of aceclofenac. It is the first described method by azo dye derivatization for the analysis of aceclofenac in bulk samples and dosage forms.
Asunto(s)
Antiinflamatorios no Esteroideos/análisis , Compuestos de Diazonio/química , Diclofenaco/análogos & derivados , Espectrofotometría/métodos , Diclofenaco/análisis , Sensibilidad y Especificidad , ComprimidosRESUMEN
The genotoxicity of a new monoazo dye series, 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes has been evaluated using human lymphocytes by alkaline comet assay. Freshly isolated human lymphocytes were exposed to the dyes (AZ-01, -02, -03 and -04) at concentrations ranging from 0 to 500 µM for 3h at 37 °C. Appropriate negative (culture medium) and positive (100 µM methyl methane sulfonate) controls were set up alongside with the dye-treated cells. Comet assay was performed to assess the extent of DNA damage. The four dyes gave varying results with respect to the parameters of DNA damage studied. AZ-01 showed concentration-dependent DNA damage (% Tail DNA) while lower concentrations (31.25-62.5 µM) did not produce any significant difference in the tail extent moment. AZ-02, the positional isomer of AZ-01, gave non-genotoxic effects at lower concentrations for the two DNA parameters. AZ-03 and AZ-04 (possessing additional C-7 substituents) did not produce significant genotoxic effect at all concentrations relative to the negative control. Two of these monoazo dyes show the potential of being used as edible colorants. The results revealed that genotoxicity of congeneric dyes bear a direct relationship to their chemical structure.
Asunto(s)
Compuestos Azo/toxicidad , Ensayo Cometa , Mutágenos/toxicidad , Naftoles/toxicidad , Células Cultivadas , Daño del ADN , Relación Dosis-Respuesta a Droga , Humanos , Técnicas In Vitro , Linfocitos/efectos de los fármacosRESUMEN
Azo-hydrazone tautomerism is a phenomenon that occurs in azo dyes possessing substituents conjugated to the azo linkage which has labile proton that can be exchanged intramolecularly. Thus the predominance of one tautomer over another is a function of many factors among which are solvent polarity, solvent type, solute-solvent interactions and the structure of the dye molecule itself. The 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes, previously shown to exhibit azo-hydrazone tautomerism, were studied for the relative predominance of one form over another based on interaction at the microenvironment of binary solvent mixtures containing DMF and non-hydrogen bonding (CCl(4)), hydrogen bond donor (toluene, chloroform), hydrogen bond acceptor (acetonitrile, acetone) and the alcohols; ethanol and methanol as solvent pairs. The three dyes gave two main bands in the 50:50 mixture of DMF with these solvents consisting of a high energy band at 250-382 nm while the low energy bands for the dyes occurred at 415-485 nm. Spectral shifts in the binary solvent mixtures were related to the solvent dipolarity, basicity of the less polar component relative to DMF, substituent type, molar transition energy, formation constant for the hydrogen-bonding solvated complexes and the standard free energy change for hydrogen bonding with DMF. The relative predominance of the hydrazone tautomer bears a direct relationship to the basicity of the solvent, presence of hydrogen bond donor substituent and was associated with high molar transition energies and low formation constant. The microenvironment surrounding the dye molecules played a major role in the stability of one tautomer relative to the other.
Asunto(s)
Compuestos Azo/química , Colorantes/química , Hidrazonas/química , Naftalenos/química , IsomerismoRESUMEN
Comprehensive electronic absorption spectra of a new dye series, 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes have been investigated in solvents of varying polarities. The solvent dependent UV-vis spectral shifts were analysed using some solvent physical parameters such as refractive index, dielectric function, hydrogen bonding acceptor ability, orientation of polarization and others. The observed spectral shifts were correlated with different solute-solvent interaction mechanisms using simple and multiple linear regression analyses. The results of the curve fitting coefficients enabled us to classify the various interactions of solvents with the dyes and relate the solvatochromic behaviours to the substituent effects on the dye molecules. Charge-transfer complexation occurring between one of the congeners and N,N'-dimethylformamide was extensively studied and discovered to be both concentration- and temperature-dependent. The electronic character and the chemical nature of the solvents as well as the chemical nature of the other substituents, apart from the common hydroxyl group, are important factors for the observed solvatochromic properties of the 4-carboxyl-2, 6-dinitrophenylazohydroxynaphthalenes.
Asunto(s)
Compuestos Azo/química , Colorantes/química , Naftoles/química , Solventes/química , Dimetilformamida/química , Estructura Molecular , Espectrofotometría UltravioletaRESUMEN
BACKGROUND: There has been an increasing interest in metabolic syndrome, but few, if any, epidemiological studies on the subject have been conducted in Nigeria. The purpose of this study was to assess the prevalence of metabolic syndrome in a Nigerian rural community. METHODS: A total of 132 participants from three rural towns in southwestern Nigeria were recruited for the study. Anthropometric variables, fasting blood glucose, triglyceride, total and high-density lipoprotein cholesterol (HDL-C), and blood pressure were assessed. The survey was carried out within 2 months after community mobilization and consent. RESULTS: The mean ages of participants were 58.6 +/- 16.9 males and 46.1 +/- 18.7 females. The overall prevalence of metabolic syndrome was found to be 12.1%, with males and females at 12.7% and 11.8%, respectively. There was no significant difference in males and females with the syndrome. Although the prevalence of abdominal obesity was higher in females than males, 16.9% and 7.3%, respectively, the men exhibited a higher mean serum level of triglyceride (P < 0.05). Only 2 (1.5%) of the males had a high fasting serum glucose level. CONCLUSIONS: These results from a representative sample of the Nigerian rural population show a high prevalence of metabolic syndrome. The large number of Nigerians with the metabolic syndrome may have important implications for the health-care sector.
Asunto(s)
Síndrome Metabólico/diagnóstico , Síndrome Metabólico/epidemiología , Adulto , Anciano , Glucemia/metabolismo , Presión Sanguínea , Índice de Masa Corporal , HDL-Colesterol/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nigeria , Prevalencia , Población Rural , Triglicéridos/metabolismoRESUMEN
Some phenyl azo hydroxynaphthalene dyes (e.g., sunset yellow) are certified as approved colorants for food, cosmetics, and drug formulations. The hydrophobicity of 4 newly synthesized azo dyes of the phenyl azo hydroxynaphthalene class was investigated, as a training set, with the goal of developing models for quantitative structure-property relationships (QSPR). Retention behavior of the molecules reversed-phase thin-layer chromatography (RPTLC) was investigated using liquid paraffin-coated silica gel as the stationary phase. Mobile phases consisted of aqueous mixtures of methanol, acetone, and dimethylformamide (DMF). Basic hydrophobicity parameter (Rmw), specific hydrophobic surface area (S), and isocratic chromatographic hydrophobicity index (phio) were computed from the chromatographic data. The hydrophobicity index (Rm) decreased linearly with increasing concentration of organic modifiers. Extrapolated Rmw values obtained by using DMF and acetone differ significantly from the value obtained by using methanol as organic modifier [P < 0.05, 1-way analysis of variance (ANOVA), Tukey's multiple comparison test]. Structure-property relationships showed that hydrophobicity was dependent on type and position of naphthalene ring substituents. Rm decreased with the presence of a highly polar substituent (e.g., COOH). Owing to intramolecular interaction, Rm increased when the common hydroxyl group (OH) is positioned ortho to the azo group, relative to para positioning, in 2 positional isomers. Pattern recognition data analysis underscores the utility of phio as a more accurate hydrophobicity descriptor than Rmw. Phio is negatively correlated with theoretically calculated density, surface tension, and refractive index for the molecules. These models could be used to predict toxicity (absorption, distribution, metabolism, excretion, toxicity; ADMET) properties of the azo dyes and may also play useful roles in computer-assisted molecular discovery of nontoxic azo dyes.
Asunto(s)
Compuestos Azo/química , Dinitrofenoles/química , Colorantes de Alimentos/química , Naftoles/química , Compuestos Azo/análisis , Cromatografía en Capa Delgada/métodos , Colorantes , Cosméticos , Dinitrofenoles/aislamiento & purificación , Colorantes de Alimentos/aislamiento & purificación , Indicadores y Reactivos , Metanol , Modelos Moleculares , Naftoles/aislamiento & purificaciónRESUMEN
This study describes a novel simple, rapid and sensitive colorimetric assay method for diclofenac sodium tablets. The method is based on a simple aromatic ring derivatization technique using newly developed 4-carboxyl-2, 6-dinitrobenzenediazonium ion (CDNBD) as chromogenic derivatizing reagent with subsequent formation of an azo dye. The diazo coupling reaction was carried out between CDNBD and diclofenac. Optimization studies for time and temperature was conducted using the method of steepest ascent. The UV absorption spectrum was recorded and the stoichiometric ratio for the drug and reagent was done by continuous variation method. Optimal calibration range was fixed (1-way ANOVA) and then the method was applied to dosage form analysis. Comparison of dosage form analysis was done with the BP HPLC method. The diazo coupling reaction is very fast and optimization studies established an optimal reaction immediately after mixing the reaction mixture in a vortex mixer for 10 sec. A new absorption maximum (lambdamax) at 470 nm was selected as analytical wavelength. The assays were linear over 1.35-10.8 microg/ml of diclofenac and the reaction required a 2:1 reagent/drug stoichiometric ratio. The new method has a low limit of detection of 0.27 microg/ml, and was reproducible over a three-day assessment of precision (RSD 2.31%). The method has been successfully applied to the assay of diclofenac sodium slow-release tablets and found to be of equivalent accuracy (p>0.05) with the official (B.P 1998) HPLC method. The new method has distinct advantages of speed, simplicity, sensitivity, and more affordable instrumentation and could find application as a rapid analytical method for diclofenac sodium tablets.
Asunto(s)
Antiinflamatorios no Esteroideos/análisis , Colorimetría/métodos , Compuestos de Diazonio , Diclofenaco/análisis , Antiinflamatorios no Esteroideos/química , Cromatografía Líquida de Alta Presión , Diclofenaco/química , Reproducibilidad de los Resultados , Espectrofotometría Ultravioleta , Comprimidos , Tecnología Farmacéutica/métodos , Temperatura , Factores de TiempoRESUMEN
The physicochemical properties of pyronaridine, a new antimalarial drug, have been determined for the first time in this study, since these parameters are comprehensively not available in literature. UV-Vis spectral analysis of both pyronaridine and its tetraphosphate salt were carried out in various solvents, in addition to solubility of the two drugs in these solvents. Partition coefficient was done in n-octanol-water mixture using the Leo-Hansch method as well hydrophobicity index determination. pKa determination was carried out on the tetraphosphate. UV-Vis spectral characteristics showed that both the base and the tetraphosphate salt have significant light absorption in the range 190-380 nm. Solubility in different solvents revealed that pyronaridine base is sparingly soluble in chloroform (1.34%) while it is slightly soluble in methanol (0.29%) and ethanol (0.42%) and very slightly soluble in octanol and distilled water. The tetraphosphate salt was sparingly soluble in water (1.46%) while it is only very slightly soluble in other solvents. The higher aqueous solubility of the salt was further revealed by a greater Rm value on extrapolation to 100% water concentration in hydrophobicity index determination. Log P value determination showed that the base {log P of 0.26+/-0.02} is more liposoluble than the salt {log P of - (1.240.21)}. Four prominent pKa values were obtained for the tetraphosphate titrated which when extrapolated to the base gave values of 7.08+/-0.05, 7.39+/-0.05, 9.88+/-0.05 and 10.30+/-0.10. The results should guide in formulation of appropriate dosage forms to improve bioavailability of the drug especially from oral routes.
Asunto(s)
Antimaláricos/química , Naftiridinas/química , 1-Octanol/química , Cromatografía en Capa Delgada , Interacciones Hidrofóbicas e Hidrofílicas , Solubilidad , Espectrofotometría Ultravioleta , Agua/químicaRESUMEN
The kinetics of thermal decomposition of 4-carboxyl-2,6-dinitrobenzenediazonium ion (CDNBD), an arenediazonium ion newly developed as a derivatizing reagent for drug analysis, are described. The arenediazonium ion, in an optimized concentrated sulfuric acid/orthophosphoric acid medium, was incubated for various time intervals at 30 degrees, 45 degrees, 55 degrees , 65 degrees , 75 degrees, and 85 degrees C. The amount of ion left after each time interval was quantified selectively by colorimetric assay at 490 nm, using mefenamic acid as a model diazo-coupling component. The rate constants for the decomposition were determined graphically. An Arrhenius plot was used to delineate the dependence of the rate constant on temperature and to predict the half-life at 25 degrees C and lower temperatures. The diazonium ion decomposed by first-order kinetics. The rate constants of decomposition, which increased progressively with temperature, were 3.18 +/- 0.41 x 10(-5), 1.19 +/- 0.07 x 10(-4), 4.87 +/- 0.15 x 10(-4), 12.88 +/- 0.73 x 10(-4), and 21.32 +/- 2.74 x 10(-4) (s(-1)) with corresponding half-lives of 363, 97.06, 23.72, 8.97, and 5.42 min at 30 degrees, 45 degrees, 55 degrees, 65 degrees, and 75 degrees C, respectively. CDNBD is highly stable in concentrated acid medium, with half-life values of about 10 h, 10 days, and 7.3 months at 25 degrees, 0 degrees, and -20 degrees C, respectively. The reagent stability profile shows that it could be readily adapted for routine applications in instrumental chemical analysis.
Asunto(s)
Compuestos de Diazonio/análisis , Acetatos/análisis , Ácido Acético/análisis , Calibración , Colorimetría , Compuestos de Diazonio/química , Relación Dosis-Respuesta a Droga , Estabilidad de Medicamentos , Almacenaje de Medicamentos , Calor , Éteres de Hidroxibenzoatos , Hidroxibenzoatos/análisis , Iones , Cinética , Ácido Mefenámico/análisis , Modelos Químicos , Nitrito de Sodio/análisis , Soluciones , Temperatura , Factores de TiempoRESUMEN
A novel colorimetric assay of propranolol tablets has been developed. The assay is based on chemical derivatization (aromatic ring derivatization technique) using diazotized 4-amino-3,5-dinitrobenzoic acid (ADBA) as the chromogenic derivatizing reagent and resultant formation of azo dyes. Optimization studies established an optimal reaction time of 5 min at 30 degrees C after mixing on a Vortex mixer the drug/reagent mixture for 10 s. A new absorption maximum (lambda(max)) was found at 470 nm, which was selected as the analytical wavelength. The assays were linear over 1-8 microg/mL propranolol, and the reaction occurred by a 1:1 reagent/drug stoichiometric ratio. The developed method has a low limit of detection of 0.76 microg/mL and is reproducible. It has been applied successfully to the assay of propranolol tablets and is of equivalent accuracy (p > 0.05) with the official (British Pharmacopoeia) ultraviolet spectrophotometric method. The new method has the main advantage of using more affordable instrumentation and could be applied to the in-process quality control of propranolol tablets.