Method Validation
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2021 ◽  
Vol 68 (1) ◽  
Hamid Zahedi ◽  
Nahid Farzi ◽  
Nasser Golestani

Abstract The main goal of this study was to determine the industrially best reductant for reduction of magnesium oxide to magnesium with wood charcoal and petroleum coke (petcoke) each in molar ratio 1:1 and 1:2 (oxidant:reductant) at high temperatures. In this study, a new and reliable combination of mathematical modeling and discrete numerical optimization theory by presenting 18 “mathematical filters” not relying only on statistical quantities of fitting (contrary to many similar researches) was introduced. The purpose of these filters was the determination of correct kinetic equation and therefore, the corresponding rate coefficient from among 18 equations most used at present in the challenging field of solid state chemical kinetics. With assistance of a new and fundamental mathematical function and the obtained values of rate coefficients, the function of rate coefficient in temperature was attained. The activation energy was then calculated as a function of temperature using the general definition of activation energy and the determined function for rate coefficient. The comparison between different reducing agents in the different conditions and with relevant previous study was accomplished to determine the best reducing agent from industry standpoint. Also, the areas under experimental data were calculated numerically and utilized for method validation and comparison. It turned out finally that relying only on fitting quantities in the solid state chemical kinetics can readily lead to wrong conclusions about the correct kinetic equation and about the most suitable reducing agent. It is obvious that the erroneous calculations and wrong decisions in the laboratory scale become significant and paramount in industry and this reveals the significance of rigorous mathematical analysis. Graphical abstract

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3015
Marwa A. Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horvath

Highly selective multifunctional magnetic nanoparticles containing a thermoresponsive polymer shell were developed and used in the sample pretreatment of urine for the assessment of lysozymuria in leukemia patients. Crosslinked poly(N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) was grown onto silica-coated magnetic nanoparticles by reversible addition fragmentation chain transfer (RAFT) polymerization. The lysozyme binding property of the nanoparticles was investigated as a function of time, protein concentration, pH, ionic strength and temperature and their selectivity was assessed against other proteins. High-abundant proteins, like human serum albumin and γ-globulins did not interfere with the binding of lysozyme even at elevated concentrations characteristic of proteinuria. A sample cleanup procedure for urine samples has been developed utilizing the thermocontrollable protein binding ability of the nanoparticles. Method validation was carried out according to current bioanalytical method validation guidelines. The method was highly selective, and the calibration was linear in the 25 to 1000 µg/mL concentration range, relevant in the diagnosis of monocytic and myelomonocytic leukemia. Intra- and inter-day precision values ranged from 2.24 to 8.20% and 1.08 to 5.04%, respectively. Intra-day accuracies were between 89.9 and 117.6%, while inter-day accuracies were in the 88.8 to 111.0% range. The average recovery was 94.1 ± 8.1%. Analysis of unknown urine samples in comparison with a well-established reference method revealed very good correlation between the results, indicating that the new nanoparticle-based method has high potential in the diagnosis of lysozymuria.

Economies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 176
Arfive Gandhi ◽  
Yudho Giri Sucahyo

The business continuity of the gig economy is strongly driven by the operator’s ability to manage the maturity of business processes. Moreover, projects in the gig economy are risky due to the lack of monitoring and involvement of actors’ profiles. When business processes become mature as the target, platform-based project results can satisfy actors’ expectations. To reach targeted maturity, operators need to standardize their business processes. This standardization is actualized in a maturity model as a benchmark and guideline tool. It exposes how mature the current business processes are and the required improvements. This research aims to construct a maturity model systematically and comprehensively to encourage operators in the gig economy (as the model user) to improve the products and services delivered. This research has constructed a new maturity model for business processes using the maturity model development phases initiated by de Bruin et al. It explores the gig economy ecosystem in Indonesia. This research initiates the maturity model by collecting 48 factors in the gig economy. It continues by composing 13 determinant candidates as representations of the factors. After an empirical test involving 200 people (consisting of gig worker, client, and operator) and two iterations of mixed-method validation involving 16 experts, this research generates ten determinants classified into three dimensions: actors, platforms, and transactions. The maturity level of each determinant is measured to indicate its position toward digital business continuity.

Bioanalysis ◽  
2021 ◽  
Gabriel Onn Kit Loh ◽  
Emily Yii Ling Wong ◽  
Yvonne Tze Fung Tan ◽  
Yi Lin Lee ◽  
Chun Keat Chew ◽  

Aim: To develop an LC-MS/MS method for simultaneous determination of duloxetine and its metabolite, 4-hydroxy duloxetine glucuronide (4HDG) in human plasma and to investigate the potential back-conversion of 4HDG to duloxetine using stability study. Materials & methods: The LC-MS/MS method was validated according to the EMA and USFDA Bioanalytical Method Validation Guidelines and applied to pilot bioequivalence study. Results & conclusion: The method validation results were within the acceptance limits. The stability study and incurred sample reanalysis results ruled out the occurrence of back-conversion. The study highlighted the conduct of back-conversion test and the advantages of LC-MS/MS method in terms of sensitivity, specificity and low consumption of organic solvents.

2021 ◽  
Vol 8 (11) ◽  
Rana Ghonim ◽  
Mohamed I. El-Awady ◽  
Manar M. Tolba ◽  
Fawzia Ibrahim

Two green-sensitive spectrofluorometric methods were investigated for assay of rupatadine (RUP) [method I] and its binary mixture with montelukast (MKT) [method II]. Method I depends on measuring native fluorescence of RUP in the presence of 0.10 M H 2 SO 4 and 0.10%w/v sodium dodecyl sulfate at 455 nm after excitation at 277 nm. The range of the first method was 0.20–2.00 µg ml −1 with detection and quantitation limits of 59.00 and 179.00 ng ml −1 , respectively. Method II depends on the first derivative synchronous spectrofluorometry. The derivative intensities were measured for the two drugs in an aqueous solution containing Mcllvaine's buffer pH 2.60 at fixed Δ λ of 140 nm. Each drug was estimated at zero-contribution of the other. The intensity was measured at 261 and 371 nm for RUP and MKT, respectively. The method was linear over 0.10–4.00 and 0.20–1.60 µg ml −1 with limits of detection 31.00 and 66.00 ng ml −1 and limits of quantitation 94.00 and 200.00 ng ml −1 for RUP and MKT, respectively. The method was extended to determine this mixture in laboratory-prepared mixtures and combined tablets. Method validation was performed according to ICH guidelines. Statistical interpretation of data revealed good agreement with the comparison method. Method greenness was confirmed by applying three different assessment tools.

C. Hazarathaiah Yadav ◽  
A. Malli Babu

Residual solvent testing is an integral part of reference material certification. A gas chromatography/flame ionization detector/headspace method has been developed and validated to detect and quantitate commonly used residual solvents in our production processes: Methanol, Tetrahydrofuran, Toluene, Dichloromethane and Dichloroethane in Simeprevir API. A simple and selective HS-GC method is described for the determination & quantification of Residual Solvents in Simeprevir API. Chromatographic separation was achieved on USP G43 equivalent capillary column Thermo Scientific™ Trace GOLD™ TG-624 SilMS, 30m × 0.32mm × 1.8µm column (P/N 26059-3390) using nitrogen as carrier gas by using different temperature gradient of FID Detectors. Linearity was observed in the range 40-120% of standard concentrations for Methanol, Tetrahydrofuran, Toluene, Dichloromethane and Dichloroethane (r2>0.999) for the amount of solvent estimated by the proposed methods was in good agreement. The proposed methods were validated. The accuracy of the methods was assessed by recovery studies at three different levels. Recovery experiments indicated the absence of interference from commonly encountered diluent and API. The method was found to be precise as indicated by the repeatability analysis, showing %RSD less than 10 for Methanol, Tetrahydrofuran, Toluene, Dichloromethane and Dichloroethane. All statistical data proves validity of the methods and can be used for routine analysis of pharmaceutical active ingredients for estimation of Residual Solvents of Methanol, Tetrahydrofuran, Toluene, Dichloromethane and Dichloroethane in Simeprevir. Baseline separation of all five solvents and Simeprevir API is achieved within 20.5 minutes of analysis time. Method validation comprised the following parameters: limit of detection (LOD), limit of quantitation (LOQ), linearity and range, accuracy, precision (repeatability and intermediate precision), system suitability, specificity, and robustness. Linearity and LOQ (ppm) are listed for each solvent in manuscript. The present method was proven to be robust and accurate for quantitative analysis of residual solvent in neat materials.

Bioanalysis ◽  
2021 ◽  
Anna Laurén ◽  
Manuela Braun ◽  
Paul Byrne ◽  
Chiara Cazzin ◽  
Kelly Colletti ◽  

Polymerase chain reaction (PCR) is widely used in various fields of laboratory testing, ranging from forensic, molecular biology, medical and diagnostic applications to a wide array of basic research purposes. COVID-19 infection testing has brought the three-letter PCR abbreviation into the vocabulary of billions of people, making it likely the most well-known laboratory test worldwide. With new modalities and translational medicine gaining importance in pharmaceutical research and development, PCR or more specifically, quantitative PCR (qPCR) is now becoming a standard tool in the (regulated) bioanalytical laboratory, driving the bioanalytical community to define best practices for method development, characterization and validation. In absence of specific guidance from health authorities, qPCR may be vulnerable to scope creep from pharmacokinetics (PK) assay validation as defined in bioanalytical method validation guidance/guidelines. In this manuscript, the European Bioanalysis Forum builds a rationale for applying context of use principles when defining requirements for qPCR assay performance and validation criteria.

2021 ◽  
Vol 58 (08) ◽  
pp. 49-53
Padmavathi P Prabhu ◽  
Paramita Das ◽  
Aditya Tari ◽  

To determine effectiveness of cleaning, analytical methods were validated for piroxicam and telmisartan. The drugs were selected on the basis of solubility in water. Water is the major solvent used for cleaning of equipments. These drugs are practically insoluble in water, so they may leave product residue even after cleaning of the equipments and necessitate lot of water for cleaning. So, any analytical method used to determine the cleanliness should be effective. During analytical method validations, following parameters were evaluated i.e. linearity, specificity, LOQ, LOD, and recovery studies by swab sampling and rinse sampling techniques. The visual cleanliness criteria was also evaluated by spiking known amount of samples on SS plates. From the results it was concluded that the developed analytical method was sensitive and accurate. For piroxicam: UV spectrophotometric analytical method was developed which showed an absorption maxima λmax at 356 nm wavelength and linearity range 0 to 25 µg/mL. Recovery of drug from swab sampling and rinse sampling techniques were found satisfactory and within the acceptance criteria. For telmisartan, UV spectrophotometric analytical method was developed which showed an absorption maxima λmax at 226 nm wavelength and linearity range 0 to 10 µg/mL. Recovery of drug from swab sampling and rinse sampling techniques were found satisfactory and within the acceptance criteria

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