scholarly journals Synchronous fluorescence as a green and selective tool for simultaneous determination of bambuterol and its main degradation product, terbutaline

2018 ◽  
Vol 5 (10) ◽  
pp. 181359 ◽  
Author(s):  
Samah Abo El Abass ◽  
Heba Elmansi
Keyword(s):  
Degradation Product ◽  
Low Cost ◽  
Reference Method ◽  
Cost Effective ◽  
Zero Crossing ◽  
Cost Effective Method ◽  
Validation Parameters ◽  
Main Degradation Product ◽  
20 Nm

A green, sensitive and cost-effective method is introduced in this research for the determination of bambuterol and its main degradation product, terbutaline, simultaneously, relying on the synchronous spectrofluorimetric technique. First derivative synchronous spectrofluorimetric amplitude is measured at Δ λ = 20 nm, so bambuterol can be quantitated at 260 nm, and terbutaline can be measured at 290 nm, each at the zero crossing point of the other. The amplitude–concentration plots were linear over the concentration ranges of 0.2–6.0 µg ml −1 and 0.2–4.0 µg ml −1 for both bambuterol and terbutaline, respectively. Official guidelines were followed to calculate the validation parameters of the proposed method. The low values of limits of detection of 0.023, 0.056 µg ml −1 and limits of quantitation of 0.071, 0.169 µg ml −1 for bambuterol and terbutaline, respectively, point to the sensitivity of the method. Bambuterol is a prodrug for terbutaline, and the latter is considered its degradation product so the established method could be regarded as a stability-indicating one. Moreover, the proposed method was used for the analysis of bambuterol and terbutaline in their single ingredient preparations and the results revealed statistical agreement with the reference method. The suggested method, being a simple and low-cost procedure, is superior to the previously published methods which need more sophisticated techniques, longer analysis time and highly toxic solvents and reagents. It could be considered as an eco-friendly analytical procedure.

THEORETICAL ANALYSES FOR LASER MACHINING MICROCHANNELS AND DEMONSTRATION OF THEIR USES IN MANUFACTURE OF A MICROFLUIDIC OPTICAL SWITCH

2006 ◽  
Vol 13 (06) ◽  
pp. 795-802 ◽  
Author(s):  
DANIEL LIM ◽  
ERNA GONDO SANTOSO ◽  
KIM MING TEH ◽  
STEPHEN WAN ◽  
H. Y. ZHENG
Keyword(s):  
Fluid Flow ◽  
Optical Switch ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Cost Effective ◽  
Laser Machining ◽  
Machining Parameters ◽  
Flow Channels ◽  
Cost Effective Method ◽  
Theoretical Analyses

Silicon has been widely used to fabricate microfluidic devices due to the dominance of silicon microfabrication technologies available. In this paper, theoretical analyses are carried out to suggest suitable laser machining parameters to achieve required channel geometries. Based on the analyses, a low-power CO 2 laser was employed to create microchannels in Acrylic substrate for the use of manufacturing an optical bubble switch. The developed equations are found useful for selecting appropriate machining parameters. The ability to use a low-cost CO 2 laser to fabricate microchannels provides an alternative and cost-effective method for prototyping fluid flow channels, chambers and cavities in microfluidic lab chips.

scholarly journals Stability-Indicating Methods for Determination of Pyritinol Dihydrochloride in the Presence of Its Precursor and Degradation Product by Derivative Spectrophotometry

2005 ◽  
Vol 88 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Mostafa A Shehata ◽  
Mohammad A El-Sayed ◽  
Mohammad G El-Bardicy ◽  
Mohammad F El-Tarras
Keyword(s):  
Hydrochloric Acid ◽  
Degradation Product ◽  
Pharmaceutical Formulations ◽  
Zero Crossing ◽  
Stability Indicating ◽  
First Derivative ◽  
Linear Relationships ◽  
Assay Methods ◽  
Powdered Form

Abstract A first-derivative spectrophotometric (1D) method and a derivative-ratio zero-crossing spectrophotometric (1DD) method were used to determine pyritinol dihydrochloride (I) in the presence of its precursor (II) and its degradation product (III) with 0.1N hydrochloric acid as a solvet. Linear relationships were obtained in the ranges of 6–22 μg/mL for the (1D) method and 6–20 μg/mL for the (1DD) method. By applying the proposed methods, it was possible to determine pyritinol dihydrochloride in its pure powdered form with an accuracy of 100.36 ± 1.497% (n = 9) for the (1D) method and an accuracy of 99.92 ± 1.172% (n = 8) for the (1DD) method. Laboratory-prepared mixtures containing different ratios of (I), (II), and (III) were analyzed, and the proposed methods were valid for concentrations of ≤10% (II) and ≤50% (III). The proposed methods were validated and found to be suitable as stability-indicating assay methods for pyritinol in pharmaceutical formulations.

Joining Dissimilar Materials Using Friction Stir Scribe Technique

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Piyush Upadhyay ◽  
Yuri Hovanski ◽  
Saumyadeep Jana ◽  
Leonard S. Fifield
Keyword(s):  
Low Cost ◽  
Dissimilar Materials ◽  
Cost Effective ◽  
High Volume ◽  
Industrial Applications ◽  
Critical Pathway ◽  
Friction Stir ◽  
Design Engineers ◽  
Cost Effective Method ◽  
Polymer Metal

Development of a robust and cost-effective method of joining dissimilar materials could provide a critical pathway to enable widespread use of multimaterial designs and components in mainstream industrial applications. The use of multimaterial components such as steel-aluminum and aluminum-polymer would allow design engineers to optimize material utilization based on service requirements and could often lead to weight and cost reductions. However, producing an effective joint between materials with vastly different thermal, microstructural, and deformation responses is highly problematic using conventional joining and/or fastening methods. This is especially challenging in cost sensitive, high volume markets that largely rely on low cost joining solutions. Friction stir scribe (FSS) technology was developed to meet the demands of joining materials with drastically different properties and melting regimes. The process enables joining of light metals like magnesium and aluminum to high temperature materials like steel and titanium. Viable joints between polymer composites and metal can also be made using this method. This paper will present the state of the art, progress made, and challenges associated with this innovative derivative of friction stir welding (FSW) in reference to joining dissimilar metals and polymer/metal combinations.

scholarly journals Application of a fast and cost-effective ‘three-in-one’ MMR ELISA as a tool for surveying anti-MMR humoral immunity: the Hungarian experience

2020 ◽  
Vol 148 ◽  
Author(s):  
K. Böröcz ◽  
Z. Csizmadia ◽  
Á. Markovics ◽  
N. Farkas ◽  
J. Najbauer ◽  
...  
Keyword(s):  
Humoral Immunity ◽  
Low Cost ◽  
Herd Immunity ◽  
Reference Method ◽  
Population Level ◽  
Cost Effective ◽  
Published Data ◽  
Mmr Vaccine ◽  
Igg Antibody ◽  
Automated Platform

Abstract In Hungary, between February 2017 and July 2019, 70 confirmed measles cases were reported, raising questions about the adequacy of population-level immunity. Although the assumed vaccination coverage is ≥99%, in a recent study, we detected potential gaps in the anti-measles humoral immunity. In Hungary, according to a decree by the Ministry of Public Welfare, beginning from 2021, the healthcare provider should conduct a serosurvey of anti-measles protection levels of healthcare professionals. To facilitate the compliance with this requirement, we developed a quick ‘three-in-one’ or ‘triple’ MMR (measles, mumps and rubella) indirect ELISA (IgG); an assay format that is currently not available commercially. High throughput applicability of the ‘three-in-one’ ELISA was verified using 1736 sera from routine laboratory residual samples, using an automated platform (Siemens BEP 2000 Advance). Assay verification was performed by comparing the full antigen repertoire-based ‘target’ assay with in-house ‘control’ assays using recombinant viral antigen coatings, and by validated commercially available kits. Indirect immunofluorescence was used as an independent reference method. Data were analysed using OriginLab, IBM SPSS, RStudio and MedCalc. In case of measles, we combined our current results with previously published data (Ntotal measles = 3523). Evaluation of anti-mumps and anti-rubella humoral antibody levels was based on the measurement of 1736 samples. The lowest anti-measles seropositivity (79.3%) was detected in sera of individuals vaccinated between 1978 and 1987. Considering the antigen-specific seropositivity ratios of all samples measured, anti-measles, -mumps and -rubella IgG antibody titres were adequate in 89.84%, 91.82% and 92.28%, respectively. Based on the virus-specific herd immunity threshold (HIT) values (HITMeasles = 92–95%, HITMumps = 75–86%, HITRubella = 83–86), it can be stated that regarding anti-measles immunity, certain age clusters of the population may have inadequate levels of humoral immunity. Despite the potential gaps in herd immunity, the use of MMR vaccine remains an effective and low-cost approach for the prevention of measles, mumps and rubella infections.

Ultrasound-Assisted Ionic Liquid-Dispersive Liquid–Liquid of Curcumin in Food Samples Microextraction and Its Spectrophotometric Determination

2019 ◽  
Vol 102 (1) ◽  
pp. 217-221 ◽  
Author(s):  
Yunus Emre Unsal ◽  
Mustafa Tuzen ◽  
Mustafa Soylak
Keyword(s):  
Ionic Liquid ◽  
Method Development ◽  
Low Cost ◽  
Cost Effective ◽  
Enrichment Factors ◽  
Food Samples ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Development Methods

Abstract Background: A rapid and new ultrasound-assisted ionic liquid-dispersive liquid–liquid microextraction method (UA-IL-DLLME) was presented for the determination of curcumin by spectrophotometry. Objective: To determine trace levels of curcumin in food samples by using green and low-cost method development. Methods: 1-Butyl-3-methylimidazolium hexafluorophosphate was used to extract curcumin from sample solutions with the aid of sonication. Optimum extraction efficiency was determined by examining extraction solvents, pH, centrifugation speed, time, sonication period, and temperature. The influences of diverse ions on the recovery of curcumin were examined. The concentration of curcumin in the final solution was measured by spectrophotometer at 425 nm. Results: The enrichment factor achieved was 167. The LOD and the RSD were 0.51 μg/L and 4.3%, respectively. The presented method was performed to detect curcumin in 20 food samples. Conclusions: The presented UA-IL-DLLME method is simple, low in cost, environmentally friendly, rapid, and sensitive and requires minimal use of toxic organic solvents. Highlights: A microextraction method was applied to increase sensitivity. Higher enrichment factors and lower detection limits were observed. The proposed technique is easy, cost-effective, accurate, and precise.

scholarly journals Different Spectrophotometric Methods for Simultaneous Determination of Trelagliptin and Its Acid Degradation Product

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Shereen Mowaka ◽  
Bassam M. Ayoub ◽  
Mostafa A. Hassan ◽  
Wafaa A. Zaghary
Keyword(s):  
Degradation Product ◽  
Simultaneous Equation ◽  
Chemometric Methods ◽  
Acid Degradation ◽  
Spectrophotometric Methods ◽  
First Derivative ◽  
Mean Centering ◽  
Validation Parameters ◽  
Major Acid

New spectrophotometric and chemometric methods were carried out for the simultaneous assay of trelagliptin (TRG) and its acid degradation product (TAD) and applied successfully as a stability indicating assay to recently approved Zafatek® tablets. TAD was monitored using TLC to ensure complete degradation. Furthermore, HPLC was used to confirm dealing with one major acid degradation product. The proposed methods were developed by manipulating zero-order, first-derivative, and ratio spectra of TRG and TAD using simultaneous equation, first-derivative, and mean-centering methods, respectively. Using Spectra Manager II and Minitab v.14 software, the absorbance at 274 nm–260.4 nm, amplitudes at 260.4 nm–274.0 nm, and mean-centered values at 287.6 nm–257.2 nm were measured against methanol as a blank for TRG and TAD, respectively. Linearity and the other validation parameters were acceptable at concentration ranges of 5–50 μg/mL and 2.5–25 μg/mL for TRG and TAD, respectively. Using one-way analysis of variance (ANOVA), the optimized methods were compared and proved to be accurate for the simultaneous assay of TRG and TAD.

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