scholarly journals Use of Pharmacokinetic Data Below Lower Limit of Quantitation Values

2012 ◽  
Vol 29 (9) ◽  
pp. 2628-2631 ◽  
Author(s):  
William J. Jusko
Keyword(s):  
Lower Limit ◽  
Pharmacokinetic Data ◽  
Limit Of Quantitation

scholarly journals Development and Validation of 13-plex Luminex-Based Assay for Measuring Human Serum Antibodies to Streptococcus pneumoniae Capsular Polysaccharides

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. e00128-18 ◽  
Author(s):  
Danka Pavliakova ◽  
Peter C. Giardina ◽  
Soraya Moghazeh ◽  
Shite Sebastian ◽  
Maya Koster ◽  
...  
Keyword(s):  
Human Serum ◽  
Lower Limit ◽  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Correlate Of Protection ◽  
Immune Correlate ◽  
Relative Standard ◽  
Limit Of Quantitation

ABSTRACT A Luminex-based direct immunoassay (dLIA) platform has been developed to replace the standardized pneumococcal enzyme-linked immunosorbent assay platform. The multiplex dLIA simultaneously measures the concentration of serum immunoglobulin G (IgG) antibodies specific for pneumococcal capsular polysaccharide (PnPS) serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F. The assay uses poly-l-lysine (PLL)-conjugated PnPS, chemically coupled to spectrally distinct Luminex microspheres. Assay validation experiments were performed using residual human serum samples obtained from 13-valent pneumococcal conjugate vaccine (13vPnC) clinical studies. Assay results are expressed as IgG antibody concentrations in micrograms per milliliter using the international reference serum, 007sp. The lower limit of quantitation (LLOQ) for all serotypes covered in the 13-plex dLIA fell within the range of 0.002 to 0.038 µg/ml serum IgG. The difference between the lower limit and upper limit of the assay range was >500-fold for all serotypes, and assay variability was <20% relative standard deviation (RSD) for all serotypes. IgG antibody measurements were shown to be serotype-specific (some cross-reactivity was observed only between the structurally related serotypes 6A and 6B as well as 19A and 19F), and no interference was observed between the serotypes when the assay was performed in the 13-plex format compared to the singleplex assays. The 13-plex dLIA platform developed by Pfizer Inc. generates up to 143 test results in a single 96-well plate and is a suitable replacement of the enzyme-linked immunosorbent assay (ELISA) platform for evaluating vaccine clinical trials. IMPORTANCE The pneumococcal enzyme-linked immunosorbent assay (ELISA) measures IgG antibodies in human serum, and it is an important assay that supports licensure of pneumococcal vaccines. The immune correlate of protection, 0.35 µg/ml of IgG antibodies, was determined by the ELISA method. Pfizer has developed a new Luminex-based assay platform to replace the ELISA. These papers describe the important work of (i) validating the Luminex-based assay and (ii) bridging the immune correlate of protection (0.35 µg/ml IgG) to equivalent values reported by the Luminex platform.

scholarly journals Development of a method for the measurement of dehydroepiandrosterone sulphate by liquid chromatography-tandem mass spectrometry

2005 ◽  
Vol 42 (6) ◽  
pp. 468-474 ◽  
Author(s):  
C A Chadwick ◽  
L J Owen ◽  
B G Keevil
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Lower Limit ◽  
Internal Standard ◽  
Tandem Mass ◽  
Dehydroepiandrosterone Sulphate ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Background: Dehydroepiandrosterone sulphate (DHEAS) is a steroid that is increasingly being recognized as a potential drug of abuse in many countries. This is due to its reputation as a hormone that may be able to retard the ageing process. The measurement of DHEAS is useful in the diagnosis of medical conditions such as congenital adrenal hyperplasia and polycystic ovary syndrome. Thus, a liquid chromatography-tandem mass spectrometry method has been developed to determine DHEAS concentrations in human serum. Method: The chromatography was performed using a WatersTM 2795 Alliance HT LC system coupled to a Mercury Fusion-RP column fitted with a SecurityGuardTM column. Results: DHEAS and the internal standard, deuterated DHEAS, both had a retention time of 1.5 min. The transition determined by the Micromass QuattroTM tandem mass spectrometer for DHEAS was m/z 367.3>96.7 and for the internal standard m/z 369.3>96.6. The method was linear up to 20 µmol/L; the lower limit of detection and the lower limit of quantitation were both 1 µmol/L. The intra- and interassay imprecision were <11% over a concentration range of 1-18 µmol/L for the in-house quality control and <12% for the intra- and interassay imprecision for the Bio-Rad Lyphocheck QC. Conclusion: The measurement of DHEAS by liquid chromatography-tandem mass spectrometry is robust and has a simple sample preparation procedure with a rapid cycle time of only 4 min.

scholarly journals Development and Application of an UHPLC-MS/MS Method for Comparative Pharmacokinetic Study of Eight Major Bioactive Components from Yin Chen Hao Tang in Normal and Acute Liver Injured Rats

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yun Wang ◽  
Xinrui Xing ◽  
Yan Cao ◽  
Liang Zhao ◽  
Sen Sun ◽  
...  
Keyword(s):  
Lower Limit ◽  
Limit Of Detection ◽  
Injury Model ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
Bioactive Ingredients ◽  
Aloe Emodin ◽  
Plasma Pharmacokinetics ◽  
Ultrahigh Performance Liquid Chromatography

Yin Chen Hao Tang (YCHT) is one of the most famous hepatoprotective herbal formulas in China, but its pharmacokinetic investigation in model rats has been rarely conducted. In this study, the hepatic injury model was caused by intraperitoneal injections of carbon tetrachloride (CCl4), and YCHT was orally administered to the model and normal rats. An ultrahigh performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method was established to analyze the plasma pharmacokinetics of eight major bioactive ingredients from YCHT in both the normal and liver injured rats. The calibration curves presented good linearity (r > 0.9981) in the concentration range. The relative standard deviation (RSD%) of inter- and intraday precision was within 9.55%, and the accuracy (RE%) ranged from -10.72% to 2.46%. The extraction recovery, matrix effect, and stability were demonstrated to be within acceptable ranges. The lower limit of detection (LLOD) and lower limit of quantitation (LLOQ) were around 0.1 ng/mL and 0.5 ng/mL, respectively, which were much lower than those in other related researches. Results reveal that there are significant differences in the pharmacokinetics of scoparone, geniposide, rhein, aloe-emodin, physcion, and chrysophanol in hepatic injured rats as compared to those in control except for scopoletin and emodin. Our experimental results provide a meaningful reference for the clinical dosage of YCHT in treating liver disorders, and the improvement of LLOD and LLOQ can also broaden the range of our method’s application, which is very suitable for quantitating these eight compounds with low levels.

scholarly journals Determination of Tianeptine in Tablets by High-Performance Liquid Chromatography with Fluorescence Detection

2007 ◽  
Vol 90 (3) ◽  
pp. 720-724
Author(s):  
Sevgi Tatar Ulu
Keyword(s):  
Lower Limit ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Linear Calibration ◽  
Fluorescence Detector ◽  
Relative Standard ◽  
Validation Parameters ◽  
Limit Of Quantitation

Abstract A sensitive and selective high-performance liquid chromatographic method has been developed for the determination of tianeptine (Tia) in tablets. The method is based on derivatization of Tia with 4-chloro-7-nitrobenzofurazan (NBD-Cl). A mobile phase consisting of acetonitrile10 mM orthophosphoric acid (pH 2.5; 77 + 23) was used at a flow rate of 1 mL/min on a C18 column. The Tia-NBD derivative was monitored using a fluorescence detector, with emission set at 520 nm and excitation at 458 nm. Gabapentin was selected as an internal standard. Linear calibration graphs were obtained in the concentration range of 45300 ng/mL. The lower limit of detection (LOD) was 10 ng/mL at a signal-to-noise ratio of 4. The lower limit of quantitation (LOQ) was 45 ng/mL. The relative standard values for intra- and interday precision were &lt;0.46 and &lt;0.57%, respectively. The recovery of the drug samples ranged between 98.89 and 99.85%. No chromatographic interference from the tablet excipients was found. The proposed method was validated in terms of precision, robustness, recovery, LOD, and LOQ. All the validation parameters were within the acceptance range. The proposed method was applied for the determination of Tia in commercially available tablets. The results were compared with those obtained by an ultraviolet spectrophotometric method using t- and F-tests.

scholarly journals Two approaches for estimating the lower limit of quantitation (LLOQ) of microRNA levels assayed as exploratory biomarkers by RT-qPCR

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Russell D. Wolfinger ◽  
Sudheer Beedanagari ◽  
Eric Boitier ◽  
Tao Chen ◽  
Philippe Couttet ◽  
...  
Keyword(s):  
Lower Limit ◽  
Limit Of Quantitation

scholarly journals A New UPLC-MS/MS Method Validated for Quantification of Jervine in Rat Plasma and the Study of Its Pharmacokinetics in Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Lianguo Chen ◽  
Qinghua Weng ◽  
Jianshe Ma
Keyword(s):  
Lower Limit ◽  
Internal Standard ◽  
Rat Plasma ◽  
Pharmacokinetic Parameters ◽  
Limit Of Determination ◽  
Limit Of Quantitation ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Reactive Monitoring ◽  
Interday Precision

The aim of this study was to develop an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to assess the concentration of jervine in rat plasma and its pharmacokinetics. Diazepam was used as internal standard (IS). The chromatographic separation of jervine and IS was carried out on an UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with a flow rate of 0.4 mL/min. A mixture of acetonitrile and water (0.1% formic acid) was used as a mobile phase. The UPLC-MS/MS was equipped with an electrospray ionization (ESI), adopting multiple reactive monitoring mode to determine jervine in rat plasma. The retention times of jervine and the internal standard were 1.71 and 2.13 min, respectively. The calibration curve of jervine ranged between 1 and 1000 ng/mL. The lower limit of quantitation (LLOQ) was 1 ng/mL, and the lower limit of determination (LLOD) was 0.2 ng/mL. The accuracy was ±6%; the interday precision and intraday precision were no more than 9%. The recovery was higher than 90.3%, and the matrix effect was lower than 10%. The UPLC-MS/MS method was successfully developed and used for the application of the pharmacokinetic study. The primary pharmacokinetic parameters of jervine in this study were as follows: the AUC(0–∞) was 969.3 ± 277.7 ng/mL·h, the Cmax was 506.6 ± 192.8 ng/mL, the CL/F was 1.7 ± 0.5 L/h/kg, and the t1/2 was 3.4 ± 1.2 h.

Accelerating ADME studies

1995 ◽  
Vol 14 (12) ◽  
pp. 991-992 ◽  
Author(s):  
L.F. Chasseaud
Keyword(s):  
Data Processing ◽  
Linear Regression Analysis ◽  
Absorbed Dose ◽  
Whole Body ◽  
Pharmacokinetic Data ◽  
Imaging Device ◽  
Limit Of Quantitation ◽  
Combustion Technology ◽  
Reproducible Method ◽  
Imaging Performance

A novel method is described for quantitative whole- body autoradioluminography using [14C]-radioactive standards prepared from rat red blood cells. MicroComputer Imaging Device model 2 (MCID) and ImageQuant (IQ) imaging systems were evaluat ed for imaging performance and autoradioluminog raphy quantitation. Weighted linear regression analysis resulted in linearity over five orders of magnitude with a lower limit of quantitation of 2.7 nCi g-1. Using IQ, 16 days were necessary for image analysis and data processing of 30 whole-body cryosections and 1080 standards. MCID reduced the image and data processing of the same cryosections and standards to only 4 days. Embedding a series of radioactive standards with each specimen in the same carboxymethyl cellulose block provided an effective method of assessing intrasection and inter section variations in thickness of whole-body cryosections. These results demonstrated that autoradioluminography provided a sensitive, accu rate, precise and reproducible method for the quan titative measurement of the tissue distribution of [14C]-radiolabelled xenobiotics in whole-body cryosections. Evaluating the biodistribution of [14C]- xenobiotics by autoradioluminography, not only provides pharmacokinetic data required for predict ing the potential tissue deposition of an absorbed dose of radioactivity in man, but also allows for visual and quantitative evaluation of radioactivity in small anatomical structures that otherwise could not be detected or measured by conventional tissue combustion technology.

Prednisolone measurement in human serum using liquid chromatography tandem mass spectrometry

2005 ◽  
Vol 42 (2) ◽  
pp. 105-111 ◽  
Author(s):  
LJ Owen ◽  
S Gillingwater ◽  
BG Keevil
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Lower Limit ◽  
Internal Standard ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
High Doses

Prednisolone is a commonly prescribed corticosteroid used in the treatment of many diseases. Despite high doses of prednisolone, some patients appear to have subtherapeutic concentrations of the drug. It would be useful to measure prednisolone in this group to determine if they have poor absorption or compliance. Hence, we have developed a liquid chromatography-tandem mass spectrometry method for the determination of prednisolone in serum. Chromatography was performed using a C18 column, giving a retention time for both prednisolone and deuterated prednisolone (internal standard) of 1.6 min. Two transitions were monitored for both prednisolone and deuterated prednisolone. These were m/z 361.2>343.0 and m/z 361.2>146.9 for prednisolone, and m/z 367.2>349.0 and m/z 367.2>149.9 for the internal standard. The intra- and inter-batch imprecision was <7% in both cases over a concentration range of 62.5-750 μg/L. The imprecision at the lower limit was 8%, the lower limit of quantitation was determined to be 30 μg/L and the method was linear up to 5000 μg/L. The method allows rapid prednisolone analysis because of a simplified sample extraction step, and has a cycle time of 3.5 min.

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