Papers by Enliven: Bio analytical Techniques
Enliven Archive, 2018
Background
Glomerular filtration rate and staging of chronic kidney disease (CKD) is typically as... more Background
Glomerular filtration rate and staging of chronic kidney disease (CKD) is typically assessed by measuring the endogenous concentrations of creatinine. Bioanalytical use of creatinine is also increasing for drug development leading to greater FDA scrutiny. Creatinine is commonly measured by the rapid and inexpensive colorimetric Jaffe reaction. However, the Jaffe reaction is notoriously inaccurate and very small shifts in creatinine cause large miscalculations in CKD staging. While attempts have been made to improve Jaffe reaction assays, an enzymatic assay for creatinine is more accurate and more stable. We review substances found in many common disease states that create chromo gens that interfere is the Jaffe reaction but do not affect the enzymatic assay. This includes cephalosporin antibiotics, glucose, and bilirubin. We also provide a framework for modifying creatinine commercial kits for drug development studies. Most creatinine kits, whether using Jaffe or enzymatic chemistry, are based on the Clinical
and Laboratory Standard Institute (CLSI) validation approach, which is designed to distinguish diseased from healthy, is not suitable for use in
drug development. The benefits of enzymatic creatinine assays have been demonstrated for over a decade yet the Jaffe reaction continues to be the primary method of measurement demonstrating the need for continued education and nuanced recommendations. For clinical lab use, we highlight a two-phase reflexive method that balances cost and accuracy. For critical decisions during a drug development study, the data strongly supports the use of the enzymatic creatinine assay in combination with bioanalytical method validation for the high accuracy needed in these settings
Enliven Archive, 2018
Industrialisation and diversification of the domains of economic–
industrial activity and activit... more Industrialisation and diversification of the domains of economic–
industrial activity and activities from farming and animal breeding domains are offering great services to society, and in same time these activities are leading advanced pollution of ambient environment. There are frequent advanced pollution in case of air with dust and toxic gases (that are producing acid rains), of soil water and of food, all these facts having negative effects on human’s health. As an example, indigenous dairy products (especially milk powder) are polluted with important amounts of nitrates, which are selftransformed in nitrites under action of some bacteria, nitrite being well known for its very high carcinogen potential
It is tried from a look dialogical, the deepening of the popular wisdom and to stretch bridges wi... more It is tried from a look dialogical, the deepening of the popular wisdom and to stretch bridges with a view to the academic opening on the part of the University for the Reunion people-university. His purpose consists of trying to explain the theoretical practical challenge of transforming the surrounding reality and the way how human beings achieve the interaction of this wisdom still in moments of crisis. Venezuelan society historically has managed occur despite the different ways of thinking and acting that coexist in it.
Simple and sensitive spectrophotometric method for the determination of thiamine (VB1) in pharmac... more Simple and sensitive spectrophotometric method for the determination of thiamine (VB1) in pharmaceutical formulations has been reported. The
proposed method is based on the reaction between the (VB1) and sodium 1,2-naphthoquine-4-sulphonate (NQS) at alkaline medium (pH 11) to
form deep brown product. Beer’s law is obeyed in the range 10-40 μg/ml of thiamine at maximum wavelength of 487 nm. Under optimized reaction
conditions, linear regression equation of the calibration curve is: A= 0.022x + 0.171 (μg/ml) with a linear correlation coefficient of 0.997.
The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.71 μg/mL and 5.18 μg/ml respectively. The method has been
successfully applied to the determination of thiamine (VB1) in pharmaceutical formulations, and can be used as a replacement of the existing
sophisticated method used in quality control laboratories.
Environmental loading of endocrine disrupting chemicals (EDCs) that originate from pharmaceutical... more Environmental loading of endocrine disrupting chemicals (EDCs) that originate from pharmaceutical wastes are known to cause adverse impacts on
aquatic life and public health. In this article, a new sensitive method has been proposed for quantification of EDCs in complicated pharmaceutical wastes
using a molecularly imprinted polymer (MIP) extraction followed by liquid chromatograph-mass spectrometer (LC-MS) analysis. The calibration curves of
EDCs showed linearity in the concentration range of 1-100 μg L-1 (r>0.996) with a 10 mL loading of pharmaceutical waste samples. The EDCs recoveries
obtained by the MIP for pharmaceutical effluents, air particulates and treated sludge were 91%, 89% and 84%, respectively; and the recovery values were
better than the conventional SPE materials such as powdered activated carbon and resin. The quantification of 17β-estradiol, a model EDC molecule,
using LC-MS showed an excellent lower limits of detection in the pharmaceutical effluents, air particulates and solid waste in the order of 0.19 μg L-1,
0.13 μg g-1, 0.12 μg g-1, respectively.
Thirteen molecular species of tetraacylglycerols in the seed oil of Physaria fendleri were recent... more Thirteen molecular species of tetraacylglycerols in the seed oil of Physaria fendleri were recently identified. We report here the quantification of the molecular species of these tetraacylglycerols using HPLC with evaporative light scattering detector and the MS of the HPLC fractions. The ion signal intensities of MS1 from the molecular species of acylglycerols with different m/z in HPLC fractions were used to estimate the ratios of the molecular species. The ratios of the molecular species of acylglycerols with the same mass were estimated by the total ion signal intensities of the fragment ions of MS2, [M + Li − FA]+ and [M + Li − FA-FA]+. The content of tetraacylglycerols was about 1%. The highest contents of the molecular species of tetraacylglycerols were from those containing one normal FA (non-hydroxylated fatty acid) and they were LsLsLsO (0.25%), LsLsLsL (0.24%), LsLsLsLn (0.21%) and LsLs-OH20:2-O (0.19%). The contents of the tetraacylglycerols containing two normal FA were lower than those containing one normal FA. Among them the highest were LsLsOL (0.10%), LsLsOO (0.06%) and LsLsOLn (0.06%).
The distribution of amino acids in hair can divulge information regarding the health (e.g., diabe... more The distribution of amino acids in hair can divulge information regarding the health (e.g., diabetes) and provide a means for detecting the history of the disease by segmentation of the hair as well as attributes of an individual (e.g., sex and age). Therefore, an nonenzymatic method of hair digestion and profiling is required. In addition to optimizing and validating a method for measuring the distribution of amino acids in human hair, a robust and comprehensive approach to objectively compare the most effective means of extracting and manipulating chromatographic data to obtain the best limits of detection, linearity, and sensitivity are provided.
Data comparisons were made by operating the mass spectrometer in a mode that rapidly switches between total ion current (TIC) and selected ion monitoring (SIM) modes during each sample injection. In this way, any external confounding factors were negated that may otherwise influence the comparison of the linearity and sensitivity between the two modes of operation. The use of SIM, peak areas, and an internal standard provided significantly better sensitivity and limits of detection than using peak heights, TICs, or no internal standard.
The sample preparation steps included protein acid hydrolysis using hydrochloric acid and trimethylsilyl (TMS) derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The optimal derivatization conditions were acetonitrile as reaction solvent, temperature of 100°C, and a reaction time of 30 min.
The method was validated by measuring the amino acid content of myoglobin. This validation was accurate for nine of the fourteen amino acids found in myoglobin and gave detection limits in the range of 0.04–0.1 μmol/L, quantitation limits in the range of 0.1–0.5 μmol/L, recoveries between 80% and 110%, and linear models with coefficients of determination (R2) greater than 0.99 in the tested range from 1 to 300 μmol/L. The remaining five amino acids of myoglobin were deleteriously affected by acid hydrolysis.
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Papers by Enliven: Bio analytical Techniques
Glomerular filtration rate and staging of chronic kidney disease (CKD) is typically assessed by measuring the endogenous concentrations of creatinine. Bioanalytical use of creatinine is also increasing for drug development leading to greater FDA scrutiny. Creatinine is commonly measured by the rapid and inexpensive colorimetric Jaffe reaction. However, the Jaffe reaction is notoriously inaccurate and very small shifts in creatinine cause large miscalculations in CKD staging. While attempts have been made to improve Jaffe reaction assays, an enzymatic assay for creatinine is more accurate and more stable. We review substances found in many common disease states that create chromo gens that interfere is the Jaffe reaction but do not affect the enzymatic assay. This includes cephalosporin antibiotics, glucose, and bilirubin. We also provide a framework for modifying creatinine commercial kits for drug development studies. Most creatinine kits, whether using Jaffe or enzymatic chemistry, are based on the Clinical
and Laboratory Standard Institute (CLSI) validation approach, which is designed to distinguish diseased from healthy, is not suitable for use in
drug development. The benefits of enzymatic creatinine assays have been demonstrated for over a decade yet the Jaffe reaction continues to be the primary method of measurement demonstrating the need for continued education and nuanced recommendations. For clinical lab use, we highlight a two-phase reflexive method that balances cost and accuracy. For critical decisions during a drug development study, the data strongly supports the use of the enzymatic creatinine assay in combination with bioanalytical method validation for the high accuracy needed in these settings
industrial activity and activities from farming and animal breeding domains are offering great services to society, and in same time these activities are leading advanced pollution of ambient environment. There are frequent advanced pollution in case of air with dust and toxic gases (that are producing acid rains), of soil water and of food, all these facts having negative effects on human’s health. As an example, indigenous dairy products (especially milk powder) are polluted with important amounts of nitrates, which are selftransformed in nitrites under action of some bacteria, nitrite being well known for its very high carcinogen potential
proposed method is based on the reaction between the (VB1) and sodium 1,2-naphthoquine-4-sulphonate (NQS) at alkaline medium (pH 11) to
form deep brown product. Beer’s law is obeyed in the range 10-40 μg/ml of thiamine at maximum wavelength of 487 nm. Under optimized reaction
conditions, linear regression equation of the calibration curve is: A= 0.022x + 0.171 (μg/ml) with a linear correlation coefficient of 0.997.
The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.71 μg/mL and 5.18 μg/ml respectively. The method has been
successfully applied to the determination of thiamine (VB1) in pharmaceutical formulations, and can be used as a replacement of the existing
sophisticated method used in quality control laboratories.
aquatic life and public health. In this article, a new sensitive method has been proposed for quantification of EDCs in complicated pharmaceutical wastes
using a molecularly imprinted polymer (MIP) extraction followed by liquid chromatograph-mass spectrometer (LC-MS) analysis. The calibration curves of
EDCs showed linearity in the concentration range of 1-100 μg L-1 (r>0.996) with a 10 mL loading of pharmaceutical waste samples. The EDCs recoveries
obtained by the MIP for pharmaceutical effluents, air particulates and treated sludge were 91%, 89% and 84%, respectively; and the recovery values were
better than the conventional SPE materials such as powdered activated carbon and resin. The quantification of 17β-estradiol, a model EDC molecule,
using LC-MS showed an excellent lower limits of detection in the pharmaceutical effluents, air particulates and solid waste in the order of 0.19 μg L-1,
0.13 μg g-1, 0.12 μg g-1, respectively.
Data comparisons were made by operating the mass spectrometer in a mode that rapidly switches between total ion current (TIC) and selected ion monitoring (SIM) modes during each sample injection. In this way, any external confounding factors were negated that may otherwise influence the comparison of the linearity and sensitivity between the two modes of operation. The use of SIM, peak areas, and an internal standard provided significantly better sensitivity and limits of detection than using peak heights, TICs, or no internal standard.
The sample preparation steps included protein acid hydrolysis using hydrochloric acid and trimethylsilyl (TMS) derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The optimal derivatization conditions were acetonitrile as reaction solvent, temperature of 100°C, and a reaction time of 30 min.
The method was validated by measuring the amino acid content of myoglobin. This validation was accurate for nine of the fourteen amino acids found in myoglobin and gave detection limits in the range of 0.04–0.1 μmol/L, quantitation limits in the range of 0.1–0.5 μmol/L, recoveries between 80% and 110%, and linear models with coefficients of determination (R2) greater than 0.99 in the tested range from 1 to 300 μmol/L. The remaining five amino acids of myoglobin were deleteriously affected by acid hydrolysis.
Glomerular filtration rate and staging of chronic kidney disease (CKD) is typically assessed by measuring the endogenous concentrations of creatinine. Bioanalytical use of creatinine is also increasing for drug development leading to greater FDA scrutiny. Creatinine is commonly measured by the rapid and inexpensive colorimetric Jaffe reaction. However, the Jaffe reaction is notoriously inaccurate and very small shifts in creatinine cause large miscalculations in CKD staging. While attempts have been made to improve Jaffe reaction assays, an enzymatic assay for creatinine is more accurate and more stable. We review substances found in many common disease states that create chromo gens that interfere is the Jaffe reaction but do not affect the enzymatic assay. This includes cephalosporin antibiotics, glucose, and bilirubin. We also provide a framework for modifying creatinine commercial kits for drug development studies. Most creatinine kits, whether using Jaffe or enzymatic chemistry, are based on the Clinical
and Laboratory Standard Institute (CLSI) validation approach, which is designed to distinguish diseased from healthy, is not suitable for use in
drug development. The benefits of enzymatic creatinine assays have been demonstrated for over a decade yet the Jaffe reaction continues to be the primary method of measurement demonstrating the need for continued education and nuanced recommendations. For clinical lab use, we highlight a two-phase reflexive method that balances cost and accuracy. For critical decisions during a drug development study, the data strongly supports the use of the enzymatic creatinine assay in combination with bioanalytical method validation for the high accuracy needed in these settings
industrial activity and activities from farming and animal breeding domains are offering great services to society, and in same time these activities are leading advanced pollution of ambient environment. There are frequent advanced pollution in case of air with dust and toxic gases (that are producing acid rains), of soil water and of food, all these facts having negative effects on human’s health. As an example, indigenous dairy products (especially milk powder) are polluted with important amounts of nitrates, which are selftransformed in nitrites under action of some bacteria, nitrite being well known for its very high carcinogen potential
proposed method is based on the reaction between the (VB1) and sodium 1,2-naphthoquine-4-sulphonate (NQS) at alkaline medium (pH 11) to
form deep brown product. Beer’s law is obeyed in the range 10-40 μg/ml of thiamine at maximum wavelength of 487 nm. Under optimized reaction
conditions, linear regression equation of the calibration curve is: A= 0.022x + 0.171 (μg/ml) with a linear correlation coefficient of 0.997.
The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.71 μg/mL and 5.18 μg/ml respectively. The method has been
successfully applied to the determination of thiamine (VB1) in pharmaceutical formulations, and can be used as a replacement of the existing
sophisticated method used in quality control laboratories.
aquatic life and public health. In this article, a new sensitive method has been proposed for quantification of EDCs in complicated pharmaceutical wastes
using a molecularly imprinted polymer (MIP) extraction followed by liquid chromatograph-mass spectrometer (LC-MS) analysis. The calibration curves of
EDCs showed linearity in the concentration range of 1-100 μg L-1 (r>0.996) with a 10 mL loading of pharmaceutical waste samples. The EDCs recoveries
obtained by the MIP for pharmaceutical effluents, air particulates and treated sludge were 91%, 89% and 84%, respectively; and the recovery values were
better than the conventional SPE materials such as powdered activated carbon and resin. The quantification of 17β-estradiol, a model EDC molecule,
using LC-MS showed an excellent lower limits of detection in the pharmaceutical effluents, air particulates and solid waste in the order of 0.19 μg L-1,
0.13 μg g-1, 0.12 μg g-1, respectively.
Data comparisons were made by operating the mass spectrometer in a mode that rapidly switches between total ion current (TIC) and selected ion monitoring (SIM) modes during each sample injection. In this way, any external confounding factors were negated that may otherwise influence the comparison of the linearity and sensitivity between the two modes of operation. The use of SIM, peak areas, and an internal standard provided significantly better sensitivity and limits of detection than using peak heights, TICs, or no internal standard.
The sample preparation steps included protein acid hydrolysis using hydrochloric acid and trimethylsilyl (TMS) derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The optimal derivatization conditions were acetonitrile as reaction solvent, temperature of 100°C, and a reaction time of 30 min.
The method was validated by measuring the amino acid content of myoglobin. This validation was accurate for nine of the fourteen amino acids found in myoglobin and gave detection limits in the range of 0.04–0.1 μmol/L, quantitation limits in the range of 0.1–0.5 μmol/L, recoveries between 80% and 110%, and linear models with coefficients of determination (R2) greater than 0.99 in the tested range from 1 to 300 μmol/L. The remaining five amino acids of myoglobin were deleteriously affected by acid hydrolysis.