scholarly journals Blood and Plasma Volumetric Absorptive Microsampling (VAMS) Coupled to LC-MS/MS for the Forensic Assessment of Cocaine Consumption

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1046 ◽  
Author(s):  
Roberto Mandrioli ◽  
Laura Mercolini ◽  
Michele Protti
Keyword(s):  
Chromatographic Analysis ◽  
Active Metabolite ◽  
Mobile Phase ◽  
Room Temperature ◽  
Forensic Assessment ◽  
Extraction Yield ◽  
Relative Standard ◽  
Aqueous Formic Acid ◽  
Volumetric Absorptive Microsampling ◽  
Good Agreement

Reliable, feasible analytical methods are needed for forensic and anti-doping testing of cocaine and its most important metabolites, benzoylecgonine, ecgonine methyl ester, and cocaethylene (the active metabolite formed in the presence of ethanol). An innovative workflow is presented here, using minute amounts of dried blood or plasma obtained by volumetric absorptive microsampling (VAMS), followed by miniaturized pretreatment by dispersive pipette extraction (DPX) and LC-MS/MS analysis. After sampling 20 µL of blood or plasma with a VAMS device, the sample was dried, extracted, and loaded onto a DPX tip. The DPX pretreatment lasted less than one minute and after elution with methanol the sample was directly injected into the LC-MS/MS system. The chromatographic analysis was carried out on a C8 column, using a mobile phase containing aqueous formic acid and acetonitrile. Good extraction yield (> 85%), precision (relative standard deviation, RSD < 6.0%) and matrix effect (< 12%) values were obtained. Analyte stability was outstanding (recovery > 85% after 2 months at room temperature). The method was successfully applied to real blood and plasma VAMS, with results in very good agreement with those of fluid samples. The method seems suitable for the monitoring of concomitant cocaine and ethanol use by means of plasma or blood VAMS testing.

Microsampling and LC–MS/MS for antidoping testing of glucocorticoids in urine

Bioanalysis ◽  
2020 ◽  
Author(s):  
Michele Protti ◽  
Roberto Mandrioli ◽  
Laura Mercolini
Keyword(s):  
Solvent Extraction ◽  
Matrix Effect ◽  
Human Urine ◽  
Room Temperature ◽  
The World ◽  
Endogenous Cortisol ◽  
Systemic Glucocorticoids ◽  
World Anti Doping Agency ◽  
Volumetric Absorptive Microsampling ◽  
Good Agreement

Background. Systemic glucocorticoids are prohibited in-competition by the World Anti-Doping Agency. Here, we describe an original microsampling workflow for the quantitation of three endogenous (cortisol, corticosterone and cortisone) and three exogenous (dexamethasone, methylprednisolone and fludrocortisone) corticosteroids in 30 μl of human urine. Materials & methods. Microsampling was carried out by dried urine spot (DUS) sampling and volumetric absorptive microsampling (VAMS), followed by solvent extraction and LC–MS/MS analysis. Results & conclusion: Good linearity (r2 > 0.9989) was obtained for all analytes; extraction yields (>81%), precision (RSD < 8.6%) and matrix effect (<12%) were satisfactory. Microsample stability at room temperature was good (analyte loss <15% after 3 months). Data obtained from real urine microsample analysis were compared with those of fluid urine, providing very good agreement (r2 > 0.9991).

scholarly journals PREPARATION AND STABILITY EVALUATION OF LL-37 CREAM

2021 ◽  
pp. 139-143
Author(s):  
ELIZA MIRANDA ◽  
KUSMARINAH BRAMONO ◽  
LUDDWI ACHMAD RIZKY ◽  
HAYUN
Keyword(s):  
Chromatographic Analysis ◽  
Mobile Phase ◽  
High Performance ◽  
Room Temperature ◽  
Limit Of Detection ◽  
Stability Evaluation ◽  
C Storage ◽  
Limit Of Quantitation ◽  
Photodiode Array ◽  
Physical Changes

Objective: The present study aimed to prepare LL-37 in a cream formulation (O/W emulsion) and evaluate its stability by determining the physical changes in the cream and concentration of LL-37 using validated high-performance liquid chromatography. Methods: The method was conducted at room temperature using a C18 column (5 µm × 250 mm × 4.6 mm) as a stationary phase, a mixture of 0.1% trifluoroacetic acid (TFA)/water (A) and 0.1% TFA/acetonitrile (B) (85:15) as the mobile phase, a flow rate of 1.0 mL/min, and photodiode array set at 228 nm as the detector. The method was validated in compliance with the Association of Official Analytical Chemists and International Conference on Harmonization guidelines. It demonstrated excellent linearity, accuracy, precision, specificity, the limit of detection, and limit of quantitation. Results: The chromatographic analysis indicated minimal degradation of LL-37 during the 12-week, with a predicted expiry time of 99 and 75 mo stored at 4 °C and 28 °C, respectively. Conclusion: LL-37 cream establishes good physical characteristics and stabilizes the active ingredient, especially at 4 °C and 28 °C storage. Therefore, the emulsion delivery system of LL-37 cream is harmless and stable as a novel alternative vehicle of LL-37.

HPLC–MS/MS studies of brimonidine in rabbit aqueous humor by microdialysis

Bioanalysis ◽  
2021 ◽  
Author(s):  
Zhan Tang ◽  
Xiumin Li ◽  
Hongyan Xu ◽  
Saizhen Chen ◽  
Binhui Wang ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
Mobile Phase ◽  
Internal Standard ◽  
In Situ Gel ◽  
Rabbit Eye ◽  
Relative Standard ◽  
Brimonidine Tartrate ◽  
Aqueous Formic Acid ◽  
Good Linear Correlation

Aim: The pharmacokinetic study of the brimonidine tartrate in situ gel in the anterior chamber of the rabbit eye was studied by microdialysis technique, and samples were analyzed by HPLC–MS/MS. Materials & methods: It was monitored in ESI mode at transition 291.9→212.0 and 296.0→216.0 for brimonidine and internal standard, respectively. Acetonitrile and 0.1% aqueous formic acid (50:50, v/v) were used as the mobile phase at 0.4 ml/min. Results & conclusion: It showed a good linear correlation between 5 and 5000 ng/ml in microdialysis solution, and the inter- and intra-day precision (relative standard deviation) was less than 4.0%. The pharmacokinetic study showed that the AUC(0-t) of in situ gel was 3.5-times than that of eyedrops, which significantly improve the bioavailability of brimonidine.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

scholarly journals Stability-indicating HPLC-DAD assay for simultaneous quantification of hydrocortisone 21 acetate, dexamethasone, and fluocinolone acetonide in cosmetics

2020 ◽  
Vol 18 (1) ◽  
pp. 962-973
Author(s):  
Saira Arif ◽  
Sadia Ata
Keyword(s):  
Mobile Phase ◽  
Limit Of Detection ◽  
Fluocinolone Acetonide ◽  
Internal Diameter ◽  
Forced Degradation ◽  
Specific Method ◽  
Regression Equations ◽  
Limit Of Quantification ◽  
Simultaneous Quantification ◽  
Relative Standard

AbstractA rapid and specific method was developed for simultaneous quantification of hydrocortisone 21 acetate (HCA), dexamethasone (DEX), and fluocinolone acetonide (FCA) in whitening cream formulations using reversed-phase high-performance liquid chromatography. The effect of the composition of the mobile phase, analysis temperature, and detection wavelength was investigated to optimize the separation of studied components. The analytes were finally well separated using ACE Excel 2, C18 AR column having 150 mm length, 3 mm internal diameter, and 2 µm particle size at 35°C using methanol with 1% formic acid and double-distilled deionized water in the ratio of 60:40 (v/v), respectively, as the mobile phase in isocratic mode. Ten microliters of sample were injected with a flow rate of 0.5 mL/min. The specificity, linearity, accuracy, precision, recovery, limit of detection (LOD), limit of quantification (LOQ), and robustness were determined to validate the method as per International Conference on Harmonization guidelines. All the analytes were simultaneously separated within 8 min, and observed retention times of HCA, DEX, and FCA were 4.5, 5.5, and 6.9 min, respectively. The proposed method showed good linearity with the correlation coefficient, R2 = 0.999 over the range of 1–150 µg/mL for all standards. The linear regression equations were y = 12.7x + 118.7 (r = 0.999) for HCA, y = 12.9x + 106.8 (r = 0.999) for DEX, and y = 12.9x + 96.8 (r = 0.999) for FCA. The LOD was 0.25, 0.20, and 0.08 µg/mL for HCA, FCA, and DEX and LOQ was 2.06, 1.83, and 1.55 µg/mL for HCA, FCA, and DEX, respectively. The recovery values of HCA, DEX, and FCA ranged from 100.7–101.3, 102.0–102.6, and 100.2–102.0%, respectively, and the relative standard deviation for precision (intra- and interday) was less than 2, which indicated repeatability and reproducibility. The novelty of the method was described by forced degradation experimentation of all analytes in the combined form under acidic, basic, oxidative, and thermal stress. The proposed method was found to be simple, rapid, and reliable for the simultaneous determination of HCA, DEX, and FCA in cosmetics.

scholarly journals METHOD VALIDATION OF RIFAMPICIN ANALYSIS IN HUMAN PLASMA AND ITS APPLICATION IN BIOEQUIVALENCE STUDY

2019 ◽  
pp. 296-303
Author(s):  
ENDANG LUKITANINGSIH ◽  
FATHUL JANNAH ◽  
RATNA BUDHI PEBRIANA ◽  
RATNA DEWI PUSPITA ◽  
TAUFIQUROHMAN . ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Bioequivalence Study ◽  
Hplc Method ◽  
Coefficient Of Determination ◽  
European Medicines Agency ◽  
Pharmacokinetic Profiles ◽  
Relative Standard ◽  
Precision And Accuracy ◽  
Bioequivalence Test

Objective: This research aims to validate the method for rifampicin analysis in plasma by using High-Performance Liquid Chromatography (HPLC) that can be used to study the bioequivalence of a generic tablet of rifampicin 450 mg “X” marketed in Indonesia. Methods: Bioequivalence test was analysed using HPLC equipped with UV-Vis detector at 377 nm. The mobile phase used was acetonitrile-phosphate buffer pH 6.8 (45:55) delivered at a flow rate of 1.5 ml/min. Bioequivalence test was conducted on a limited number of subjects (n=8). The subjects were divided into two groups randomly. The pharmacokinetic profiles of the test tablet and reference tablet were statistically calculated using SPSS program to see the test tablet and reference tablet were bioequivalence or not. Results: The developed HPLC method for rifampicin analysis in plasma was sufficiently valid based on the International Conference on Harmonization (ICH) and European Medicines Agency (EMA) guideline, with precision and accuracy values were % Relative Standard Deviation (% RSD = 1.40–13.04) and % Recovery (86.24–102.13), respectively. Meanwhile, the method was linear over studied concentration (0.05 to 10.26 µg/ml) with a coefficient of determination (R2) = 0.9984. The method also had good stability and sensitivity. The result of statistical calculation showed that the generic rifampicin tablet X was bioequivalence toward the reference tablet Rimactan 450 mg. Conclusion: The test rifampicin tablet that was, the generic tablet “X” was bioequivalence toward the reference rifampicin tablet “Rimactan”.

Defect Structure of MEV Si Implantation in GaAs

1988 ◽  
Vol 126 ◽  
Author(s):  
S.-Tong Lee ◽  
G. Braunstein ◽  
Samuel Chen
Keyword(s):  
Free Surface ◽  
Defect Structure ◽  
Room Temperature ◽  
Surface Region ◽  
Peak Position ◽  
Lattice Disorder ◽  
Depth Profiles ◽  
Trim Calculation ◽  
Good Agreement

ABSTRACTThe defect and atomic profiles for MeV implantation of Si in GaAs were investigated using He++ channeling, TEM, and SIMS. Doses of 1–10 × 1015Si/cm2 at 1–3 MeV were used. MeV implantation at room temperature rendered only a small amount of lattice disorder in GaAs. Upon annealing at 400°C for 1 h or 800°C for 30 a, we observed a ‘defect-free’ surface region (- 1 μ for 3 MeV implant). Below this region, extensive secondary defects were formed in a band which was 0.7 μ wide and centered at 2 μ for 3 MeV implant. These defects were mostly dislocations lying in the [111] plane. SIMS depth profiles of Si implants showed the Si peak to be very close to the peak position of the defects. The experimental profiles of Si were compared to the TRIM calculation; generally good agreement existed among the peak positions.

Analysis of Thermal Variation of Length and Refractive Index of Lead Fluoride to Study its Optical Properties

1989 ◽  
Vol 172 ◽  
Author(s):  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day
Keyword(s):  
Refractive Index ◽  
Room Temperature ◽  
Linear Thermal Expansion ◽  
Small Variation ◽  
Published Data ◽  
Thermal Variation ◽  
Lead Fluoride ◽  
Superionic Phase Transition ◽  
Lorenz Relation ◽  
Good Agreement

AbstractLinear thermal expansion and refractive index variation have been measured in lead fluoride with a laser interferometer as a function of temperature. Data has been analyzed using the Lorentz-Lorenz relation. Molecular polarizability, band gap, variation of refractive index with density, and strain-polarizability parameter have been studied as a function of temperature. They exhibit a small variation with temperature except near the superionic phase transition where the variation appears to be more pronounced. The results are in good agreement with the published data near room temperature.

RP-HPLC METHOD DEVELOPMENT FOR THE ASSAY OF AMPHOTERICIN B

INDIAN DRUGS ◽  
2014 ◽  
Vol 51 (02) ◽  
pp. 16-20
Author(s):  
L Mohankrishna ◽  
◽  
P. J. Reddy ◽  
B. P Reddy. ◽  
P. Navya
Keyword(s):  
Amphotericin B ◽  
Mobile Phase ◽  
Method Development ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Ich Guidelines ◽  
Relative Standard ◽  
Phase Combination ◽  
Hplc Method Development

A sensitive and precise HPLC procedure has been developed for the assay of amphotericin B in bulk samples and pharmaceutical formulations by using a C18 column [Kromosil, C18, (5 µm, 4.6mm x 250 mm; Make. Waters)], and mobile phase combination is 1% formic acid in water and acetonitrile in ratio of 45:55 V/V. The procedure has been validated as per the ICH guidelines. The λmax of detection was fixed at 407 nm, so that there was less interference from mobile phase with highest sensitivity according to UV analysis. Calibration plots were linear in the range of 10-100 µg/mL and the LOD and LOQ were 0.02 µg/mL and 0.06 µg/mL respectively. The high recovery and low relative standard deviation confirm the suitability of the method for routine quality control determination of amphotericin B in different formulations.

Development of Enzyme-Linked Immunoassay Systems for Monitoring the Content of the Main Non-Meat Additives in Meat Products

2021 ◽  
Vol 37 (5) ◽  
pp. 117-122
Author(s):  
E.A. Zvereva ◽  
O.D. Hendrickson ◽  
B.B. Dzantiev ◽  
A.V. Zherdev
Keyword(s):  
Trypsin Inhibitor ◽  
Room Temperature ◽  
Meat Products ◽  
Reaction Medium ◽  
Soybean Trypsin Inhibitor ◽  
Russian Science ◽  
Additional Advantage ◽  
Relative Standard ◽  
Total Analysis ◽  
Kinetic Mode

Abstract-Methods for control of the content of non-meat components (connective tissue of animals, eggs, soybeans) in meat products have been developed based on competitive enzyme immunoassay of biomarker proteins: collagen, ovalbumin, and soybean trypsin inhibitor. Polyclonal rabbit antibodies against the biomarkers were produced. Screening of the following analysis conditions was carried out using the most affine preparations: the duration of the stages, the concentrations of the reagents, the composition of the reaction medium to ensure the completeness and the minimum limits of detection of analytes. It was shown that the immunochemical stage can be transferred to the kinetic mode and reduced to 20 min, while the total analysis took only 1 h. The selected conditions synchronized detection stages and provided the same signal amplitudes from all three biomarkers. An additional advantage of the method is that the analysis can be carried out at room temperature. The detection limits for collagen, ovalbumin and soybean trypsin inhibitor in the final extracts were 0.025 μg/mL, 0.012 μg/mL, and 0.001 μg/mL, respectively. Approbation of the method showed the reliability of the conclusions about the composition of the tested meat products; the relative standard deviation in the analysis of the monitored biomarkers was 8-10%. Key words: enzyme-linked immunoassay, meat products, collagen, ovalbumin, soybean trypsin inhibitor The work was financially supported by the Russian Science Foundation (project no. 19-16-00108).

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