|
| ||
|
|
||
Calibration Standards (calibration + standards)
Selected AbstractsNanoscale Calibration Standards and Methods.CHEMPHYSCHEM, Issue 1 2006Dimensional, Nanometer Range., Related Measurements in the Micro- No abstract is available for this article. [source] Determination of picroside II in dog plasma by HPLC and its application in a pharmacokinetics studyBIOMEDICAL CHROMATOGRAPHY, Issue 4 2005Fu-Chuan Yang Abstract A sensitive and simple high-performance liquid chromatography method with UV detection was developed and validated for determining picroside II in dog plasma. Paeoni,orin was employed as internal standard and the sample pre-treatment procedure consists of deproteinization by addition of acetonitrile. Chromatographic separations were performed on a Shimadzu VP-ODS column (250 × 4.6 mm i.d., 5 µm). The mobile phase consisted of acetonitrile,0.1% acetic acid aqueous (v/v), 23:77, v/v, at a rate of 1 mL/min. Detection was carried out at a wavelength of 266 nm. Calibration standards ranged from 0.25 to 500 µg/mL in dog plasma and the mean correlation coef,cient of 0.9981 was found for the linear calibration curves (n = 6). The limit of quanti,cation (LOQ) was 0.25 µg/mL. Intra- and inter-assay RSD ranged from 0.70 to 7.5%. Accuracy (%bias) ranged from ,6.3 to 6.0%. This method was applied to the pharmacokinetic study of picroside II in dogs. The study demonstrated the plasma picroside II concentration,time curves were ,tted to the two-compartment open model and showed linear pharmacokinetics. Copyright © 2005 John Wiley & Sons, Ltd. [source] Performance of calibration standards for antigen quantitation with flow cytometry in chronic lymphocytic leukemiaCYTOMETRY, Issue 6 2007Eva D. Rossmann Abstract Background: The fluorescence intensities of CD3, CD4 on T cells and CD20, CD22 molecules on B cells were quantitatively measured on lymphocytes from chronic lymphocytic leukemia (CLL) patients and healthy donors. Methods: The performance of three different types of microbeads was compared, i.e. Quantum molecules of equivalent soluble fluorochrome (Q-MESF), Quantum simply cellular (QSC), and QuantiBRITEÔ (QB). As all PE-conjugates had a F/P ratio of 1:1, the MESF units represented also the antibody binding capacity (ABC). Results: The ABCs of CD4 and CD20 antigens estimated with QSC (ABCQSC) were higher than those assigned with QB (ABCQB) with an average difference 49%. Higher numbers of antigenic sites were obtained with Q-MESF than with QSC for CD20 antigen. On the contrary, CD4 antigenic sites numbers estimated with QSC were higher than those estimated with Q-MESF. ABC values estimated with Quantum MESF PE (ABCQ-MESF) were ,15% higher than ABCQSC, whereas ABCQ-MESF was ,49% higher than ABCQB. Statistically significant correlations were found between the values obtained using various standards. The present study is the first to report down-regulation of CD3 antigen on T cells from patients with CLL. Conclusions: This study emphasizes the relevance of quantitative measurement of fluorescence intensity by flow cytometry as a standardized approach to measure and interpret the expression of some CLL markers and reduce variability of results obtained at different sites in multi-center clinical studies. © 2007 Clinical Cytometry Society [source] Electromigration diffusivity spectrometry: A way for simultaneous determination of diffusion coefficients from mixed samplesELECTROPHORESIS, Issue 17 2010Suhua Yang Abstract A novel method was proposed for simultaneous measurement of diffusion coefficients, (D), from mixed samples by electrophoresis and termed electromigration-based diffusivity spectrometry. After theoretical treatment, D- equation for practical use has been deduced. With a modified CE system built in laboratory, electromigration-based diffusivity spectrometry has been realized and validated to suit for fast and accurate determination of diffusivities of mixed aromatic amino acids, phenols and aromatic organic acid, giving diffusivity spectra by peak area versus D, much similar to mass spectra. The precision of the measurement was found to critically depend on pH value of running buffer, which should be so selected that the analytes and internal standards could be charged at above 0.5e. The standards have to be selected at an electric flux far from each other and from analytes. In these cases, sample and running buffer concentrations, voltage and system temperature were found to have only negligible impact on the determination. In our test, the obtained measuring precision was generally kept within 1% for five runs, and the measured values of D agreed well with those from literature, with a deviation of less than 2.2% after the right use of calibration standards. [source] Measurement of a reciprocal four-port transmission line structure using the 16-term error modelMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2007Yun Zhang Abstract A new method to measure reciprocal four-port structures, using a 16-term error model, is presented. The measurement is based on 5 two-port calibration standards connected to two of the ports, while the network analyzer is connected to the two remaining ports. Least-squares-fit data reduction techniques are used to lower error sensitivity. The effect of connectors is deembedded using closed-form equations. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1511,1515, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22498 [source] Development of a liquid chromatography/tandem mass spectrometry assay for the quantification of PM02734, a novel antineoplastic agent, in dog plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2006Jianming Yin A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay was developed and validated to quantify a novel antineoplastic agent, PM02734, in dog plasma. The method was validated to demonstrate the specificity, limit of quantification (LOQ), accuracy, and precision of measurements. The calibration range for PM02734 was established using PM02734 standards from 0.05 to 100,ng/mL in blank plasma. The dominating ions were doubly charged molecular ions [M+2H]2+ at m/z 740.0 instead of singly charged ones at m/z 1478.4. The selected reaction monitoring (SRM), based on the m/z 740.0,,,212.2 transition, was specific for PM02734, and that based on the m/z 743.8,,,212.2 transition was specific for deuterated PM02734 (the internal standard, IS); no endogenous materials interfered with the analysis of PM02734 and IS from blank plasma. The assay was linear over the concentration range 0.05,100,ng/mL. In terms of sensitivity of assay 0.05,ng/mL is a very low LLOQ, especially considering PM02734 is a peptide. The correlation coefficients for the calibration curves ranged from 0.9990 to 0.9999. The mean intraday and interday accuracies for all calibration standards (n,=,9) ranged from 93 to 111% (,11% bias) in dog plasma, and the mean interday precision for all calibration standards was less than 6.4%. The mean intra- and interday assay accuracy for all quality control replicates in dog plasma (n,=,9), determined at each QC level throughout the validated runs, ranged from 85,111% (,15% bias) and from 99,109% (,9% bias), respectively. The mean intra- and interday assay precision was less than 12.1 and 13.3% for all QC levels, respectively. The assay has been used to support preclinical pharmacokinetic (PK) and toxicokinetic studies. The results showed that preclinical samples could be monitored for PM02734 up to 168,h after dosing, which allowed us to identify multiple elimination phases and accurately estimate PK information. Copyright © 2006 John Wiley & Sons, Ltd. [source] Pharmacokinetic measurements of IDN 5390 using electrospray ionization tandem mass spectrometry: structure characterization and quantification in dog plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2005Liguo Song In this report, electrospray ionization tandem mass spectrometry (ESI-MS/MS) for a pharmacokinetic study of IDN 5390, a novel C- seco taxane derivative, which is under preclinical evaluation, has been investigated. Our results showed that IDN 5390 and other taxanes including paclitaxel and IDN 5109 could ionize well in not only positive-, but also in negative-ion mode. Under collision-induced dissociation (CID) conditions, these compounds could fragment into similar M- (molecular), T- (taxane ring) and S- (side chain) series ions. In positive-ion ESI, the formation of both T- and S-series ions involved the breaking of the C-13 ester bond. In negative-ion ESI, however, while the formation mechanism of S-series ions remained the same, the breaking of the C-1, carboxylic ester bond resulted in T-series ions. At optimum collision energy (CE) values, M-, T- and S-series ions of IDN 5390 in both positive- and negative-ion ESI-MS/MS spectra had good intensity. This phenomenon makes both positive- and negative-ion ESI-MS/MS good methods for IDN 5390 metabolite structural characterization, i.e. to reveal the location of modification groups in IDN 5390 metabolites versus IDN 5390 either on the side chain or the taxane ring. A liquid chromatography (LC)/ESI-MS/MS method using the multiple-reaction monitoring (MRM) technique was thereafter developed to quantify IDN 5390 in dog plasma using paclitaxel as internal standard. The method was validated using a concentration range between 5 and 1000,ng/mL and had a limit of detection of 1,ng/mL. The inter-day %CV (%coefficient of variation) of the calibration standards ranged between 4.36 and 9.64%, the intra-day %CV of the calibration standards between 0.61 and 13.44%, and the mean % accuracy of the quality control samples at the low, middle and high end of the concentration curves were 12.5, 6.8 and 9.6%, respectively. Copyright © 2005 John Wiley & Sons, Ltd. [source] A direct injection high-throughput liquid chromatography tandem mass spectrometry method for the determination of a new orally active ,v,3 antagonist in human urine and dialysateRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2003Wei Zeng A generic high-throughput liquid chromatography (HTLC) tandem mass spectrometry (MS/MS) assay for the determination of compound I in human urine and dialysate (hemodialysis) was developed and validated. By using the HTLC on-line extraction technique, sample pretreatment was not necessary. The sample was directly injected onto a narrow bore large particle size extraction column (50,×,1.0,mm, 60,,m) where the sample matrix was rapidly washed away using a high flow rate (5,mL/min) aqueous mobile phase while analytes were retained. The analytes were subsequently eluted from the extraction column onto an analytical column using an organic-enriched mobile phase prior to mass spectrometric detection. The analytes were then eluted from the analytical column to the mass spectrometer for the determination. The linear dynamic range was 2.0,6000,ng/mL for the urine assay and 0.1,300,ng/mL for the dialysate assay. Intraday accuracy and precision were evaluated by analyzing five replicates of calibration standards at all concentrations used to construct the standard curve. For the urine assay, the precision (RSD%, n,=,5) ranged from 1.9 to 8.0% and the accuracy ranged from 87.8 to 105.2% of nominal value. For the dialysate assay, the precision (RSD%, n,=,5) ranged from 1.1 to 10.0% and the accuracy from 94.5 to 105.2% of nominal value. In-source fragmentation of the acyl glucuronide metabolite (compound III) did not interfere with the determination of parent compound I. The developed HTLC/MS/MS methodology was specific for compound I in the presence of compound III. Column life-time is increased and sample analysis time is decreased over traditional reversed-phase methods when direct injection assays for urine and dialysate are coupled with the technology of HTLC. Copyright © 2003 John Wiley & Sons, Ltd. [source] LC-MS/MS determination of 2-(4-((2-(2S,5R)-2-Cyano-5-ethynyl-1-pyrrolidinyl)-2-oxoethylamino)-4-methyl-1-piperidinyl)-4-pyridinecarboxylic acid (ABT-279) in dog plasma with high-throughput protein precipitation sample preparationBIOMEDICAL CHROMATOGRAPHY, Issue 11 2007Joseph Kim Abstract As an effective DPP-IV inhibitor, 2-(4-((2-(2S,5R)-2-Cyano-5-ethynyl-1-pyrrolidinyl)-2-oxoethylamino)-4-methyl-1-piperidinyl)-4-pyridinecarboxylic acid (ABT-279), is an investigational drug candidate under development at Abbott Laboratories for potential treatment of type 2 diabetes. In order to support the development of ABT-279, multiple analytical methods for an accurate, precise and selective concentration determination of ABT-279 in different matrices were developed and validated in accordance with the US Food and Drug Administration Guidance on Bioanalytical Method Validation. The analytical method for ABT-279 in dog plasma was validated in parallel to other validations for ABT-279 determination in different matrices. In order to shorten the sample preparation time and increase method precision, an automated multi-channel liquid handler was used to perform high-throughput protein precipitation and all other liquid transfers. The separation was performed through a Waters YMC ODS-AQ column (2.0 × 150 mm, 5 µm, 120 Å) with a mobile phase of 20 mm ammonium acetate in 20% acetonitrile at a flow rate of 0.3 mL/min. Data collection started at 2.2 min and continued for 2.0 min. The validated linear dynamic range in dog plasma was between 3.05 and 2033.64 ng/mL using a 50 µL sample volume. The achieved r2 coefficient of determination from three consecutive runs was between 0.998625 and 0.999085. The mean bias was between ,4.1 and 4.3% for all calibration standards including lower limit of quantitation. The mean bias was between ,8.0 and 0.4% for the quality control samples. The precision, expressed as a coefficient of variation (CV), was ,4.1% for all levels of quality control samples. The validation results demonstrated that the high-throughput method was accurate, precise and selective for the determination of ABT-279 in dog plasma. The validated method was also employed to support two toxicology studies. The passing rate was 100% for all 49 runs from one validation study and two toxicology studies. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||