Green synthesis of silver nanoparticles by aqueous extract of Dovyalis abyssinica fruit for antibacterial applications

Green biosynthesis technique was employed to synthesize silver nanoparticles (AgNPs). Fresh citrus fruit of Dovyalis abyssinica (vernacular name Koshim) tree was extracted by distilled water to obtain phenolic natural compounds that have reducing capacity of metallic ions to the corresponding metallic nanoparticles, in this case, silver ion to silver nanoparticles. The appearance of the UV-Vis absorbance peak at 430 nm and the color change from pale yellow reaction mixture to reddish brown colored product solution have confirmed the formation of AgNPs. FTIR data has also shown the presence of organic components from the plant with the particles that may be used as capping agents to stabilize the formed particles and to control the size. The prepared nanoparticles and the plant extract have shown antibacterial property against E. coli and S. aureus, though the effect of the AgNPs was better than the plant extract. This study contributes for the development of environmentally friendly procedures in the preparation of nanoparticles for medicine, energy or environment.

OPTIMIZED AND VALIDATED SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF AMPICILLIN IN PHARMACEUTICAL FORMULATIONS

Objective: A simple, precise, and accurate spectrophotometric method has been developed to determine Ampicillin in pharmaceutical formulations. Methods: The proposed method, based on the carboxylic acid group reaction, present in Ampicillin with a mixture of KIO3 and KI, form a yellow-colored product in an aqueous medium. The response was allowed to proceed at 25±1 °C, and absorbance measured after 5 min against a reagent blank prepared simultaneously using a UV-Vis spectrophotometer. The parameters verified were specificity, linearity, linearity range, accuracy, precision, detection limit, quantitation limit, robustness, and ruggedness. Results: The yellow-colored product was measured at 352 nm against the reagent blank using UV–Vis spectrophotometer. The linear dynamic range of concentration was 0.25–2.5 µg/ml with a correlation coefficient of 0.9999. The LOD, LOQ values to be 0.086 and 0.261 µg/ml, respectively, for the proposed method. The percentage of recoveries was 98.27–100.89% with an acceptable relative standard deviation (±2%). The robustness and ruggedness values were excellent. Conclusion: The ICH guidelines for pharmaceuticals and human use were followed and applied to validate the proposed method. The method was compared with available literature and found similar results that confirmed the reliability and effective way for Ampicillin's determination.

Determination of Eugenol in Personal-Care Products by Dispersive Liquid-Liquid Microextraction Followed by Spectrophotometry Using p-Amino-N,N-dimethylaniline as a Derivatizing Agent

Two simple methods for the determination of eugenol were developed. The first depends on the oxidative coupling of eugenol with p-amino-N,N-dimethylaniline (PADA) in the presence of K3[Fe(CN)6]. A linear regression calibration plot for eugenol was constructed at 600 nm, within a concentration range of 0.25-2.50 μg.mL–1 and a correlation coefficient (r) value of 0.9988. The limits of detection (LOD) and quantitation (LOQ) were 0.086 and 0.284 μg.mL–1, respectively. The second method is based on the dispersive liquid-liquid microextraction of the derivatized oxidative coupling product of eugenol with PADA. Under the optimized extraction procedure, the extracted colored product was determined spectrophotometrically at 618 nm. A linear plot within a concentration range of 0.05–1.65 μg.mL–1 (r = 0.9997) was constructed. The LOD and LOQ were 0.053 and 0.177 μg.mL–1, respectively. Both methods were tested for the analysis of eugenol in commercial personal-care products, and the results confirmed that the procedures are accurate, precise, and reproducible (RSD < 1%).

Growth of Ga2O3 Nanowires by a Vapor Transport Method and their Optical Transmittance Spectra

Gallium oxide (Ga2O3) nanowires were grown on fused quartz and Si substrates by a vapor transport method of heating gallium metal at 750−1100 °C in a tube of the horizontal furnace. The obtained white colored product has shown to be the Ga2O3 nanowires with average diameters ranging from 30 to 80 nm. The optical transmittance spectra indicated that the bandgap energy of Ga2O3 nanowire increases as the diameter of nanowire decreases.

Spectrophotometric Determination of Azithromycin using Oxidative Coupling Reaction

For determining the azithromycin (AZT) in medicinal and pure formulas, a simple spectrophotometric technique was developed. An approach suggested is dependent on an AZT’s oxidative coupling reaction by sodium period (SPI) and 4-amino antipyrine (AAP) producing a pink colored compound with optimum absorption of 480 nm. Different experimental parameters are extensively researched and mastered, which affects the stability of a colored product formed, then developed. The law of the Beer is obeyed over its concentration range 3 to 44 ppm, whereas the limit of detection and quantification is 0.1908 and 0.5726 ppm, respectively, for a connection factor (r) = 0.9998. Also calculated are the molar absorption of 8.23 × 103 L/mol.cm, and the sensitivity index for Sandell is 7 × 10-5 mg/cm2. A method’s accuracy and precision are tested by also determining a relative standard deviation (RSD) less than 0.645 percent, and 100.189 percent average recovery. Practically possible external interferences about a calculation for AZT are checked in drug tablets. The results demonstrated that the procedure for determining AZT was successful in its application in pharmaceutical preparations. Comparing the literature survey that shows good sensitivity and selectivity, the reliability of the proposed method is chalked in.

Oxidative Coupling Reaction for Micro Trace Analysis of Mebendazol Residual with p-bromoaniline in Presence of n- bromosuccinimide

Rapid, reproducible and accurate method has been developed for the assay for of mebendazol (MBZ) residual assay. The method is based on alkaline hydrolysis of MBZ with sodium hydroxide then oxidation with N-bromosuccinimide (NBS) followed by coupling with 4-Bromoaniline (4-BA) to yield a highly colored product absorbed at maximum 434 nm. Regression analysis of linearity range was found (0.6-2.8) µg.ml-1. The optimum conditions that affect the oxidation were studied. The developed method was found to be precise with mean value of relative standard deviation (1.153- 1.303) and accurate with relative error (-0.5940-1.7821) .The calculated molar absorptivity and sandal sensitivity values of (29825 L.mol-1.cm-1), 0.0099 µg.cm-2 respectively. The limit of detection and limit of quantitation were of 0.04696, 0.156548 µg.ml-1 respectively .The suggested method showed good recovery with a mean value of 100.77% for analysis of dosage forms.

Activity of enzymes of tyrosine metabolism in the rat liver under the conditions of acetaminophen-induced hepatitis on the background of protein deficiency

The contribution of the mis-metabolism of individual amino acids to the development of drug-induced damage to liver cells remains unexplored. The aim of the present study was to investigate the changes in liver tyrosine level and activity of the enzymes of its metabolism: tyrosine aminotransferase, 4-hydroxyphenylpyruvate dioxygenase, aldehyde dehydrogenase ALDH3A1 under the conditions of acetaminophen-induced hepatitis on the background of protein deficiency. Determination of tyrosine in deproteinized with 6% sulfosalicylic acid extracts of the liver tissue was performed using the automatic analyzer of amino acids T-339 (“Microtechnology”, Czech Republic). The enzyme activity was determined by spectrophotometric method – tyrosine aminotransferase by the amount of 4-hydroxybenzaldehyde, which has a maximum absorption at 330 nm, 4-hydroxyphenylpyruvate dioxygenase – by the colored product intensity at λ 336 nm, aldehyde dehydrogenase ALDH3A1 activity was measured at 340 nm wavelength. Results have shown that in animals with toxic liver injury which were maintained in conditions of alimentary protein deficiency, a 5-fold decrease in tyrosine level in the liver was observed. At the same time in animals of this group there was a decrease in TAT activity by 1.6 times, a 4-fold decrease in activity of aldehyde dehydrogenase ALDH3A1 and increase in the activity of 4-hydroxyphenylpyruvate dioxygenase by 2.5 time comparing to control parameters. Conclusion was made, that alimentary protein deficiency is a factor leading to an intensification of tyrosine metabolism disturbances in animals with toxic liver injury. The pronounced exhaustion of the tyrosine pool is accompanied by the activation of the homogentisate pathway of its metabolism, as evidenced by the increase in the activity of 4-hydroxyphenylpyruvate dioxygenase and simultaneous reduction in the aldehyde dehydrogenase ALDH3A1activity. The established changes open prospects to study the possible targets for the exogenous correction of metabolic disorders under the conditions of intoxication with acetaminophen, especially in people with protein deficiency.

Progress Towards Colorimetric and Fluorescent Detection of Carbonyl Sulfide

<p>We report here that a fluorescent benzobisimidazolium salt (TBBI) can be used for the fluorescent and colorimetric detection of carbonyl sulfide (COS) over related heterocumulenes including CO₂ and CS₂ in wet MeCN. The reaction between TBBI and COS in the presence of fluoride yields a highly fluorescent (l_em = 354 nm) and colored product (l_ex = 321 nm), that is readily observed by the naked eye. We view these results as a first step toward developing activity-based probes for COS detection.</p>

Progress Towards Colorimetric and Fluorescent Detection of Carbonyl Sulfide

<p>We report here that a fluorescent benzobisimidazolium salt (TBBI) can be used for the fluorescent and colorimetric detection of carbonyl sulfide (COS) over related heterocumulenes including CO₂ and CS₂ in wet MeCN. The reaction between TBBI and COS in the presence of fluoride yields a highly fluorescent (l_em = 354 nm) and colored product (l_ex = 321 nm), that is readily observed by the naked eye. We view these results as a first step toward developing activity-based probes for COS detection.</p>

Colorimetric detection of glyphosate: towards a handmade and portable analyzer

Glyphosate (GFT) is a widely used herbicide, considered toxic and a probable carcinogen. The main challenge is its detection, usually requiring expensive and laborious methodologies. Herein, we report a colorimetric detection of GFT, using a derivatization reaction with 2,4-dinitrofluorobenzene (DNFB) that leads to a yellow-colored product. This is undertaken under mild conditions (weakly basic aqueous medium and ambient conditions). A thorough kinetic study was carried out, showing that the derivatization reaction with GFT predominates over the hydrolysis of DNFB. Hence, the colorimetric product is the major product formed, which was fully characterized by nuclear magnetic resonance. Finally, a portable, handmade and cheap colorimeter was used to detect and quantify GFT, relying on the colorimetric reaction proposed. Simulating real contaminated samples, it was possible to analyze in just 10 min, with less than 7 % of error of the nominal concentration. Overall, a highly sustainable approach is shown for an herbicide monitoring, with a simple and mild derivatization reaction that does not require purification and leads to a colorimetric product. Moreover, a simple apparatus with low time analysis is proposed that uses a problematic electronic trash: cellphone chargers. This cheapens the process and allows field analysis that can be extended to other agrochemicals.