Monday, 8 August 2016

Total Serum Fatty Acid Analysis by GC-MS: Assay Validation and Serum Sample Stability

Author(s):

Jianwei Ren, Ellen L. Mozurkewich, Ananda Sen, Anjel M. Vahratian, Thomas G. Ferreri, Alexander N. Morse and Zora DjuricPages 331-339 (9)

Abstract:


Analysis of n3 fatty acids in serum samples has clinical applications in supplementation trials, but the analysis can be challenging due to low levels, stability issues and intra-individual variation. This study presents the single laboratory validation of a gas chromatographic-mass spectral (GC-MS) assay for analysis of fatty acid methyl esters (FAME) using sensitive single ion monitoring and provides data on fatty acid stability under different sample handling conditions. Recovery of total fatty acids from serum with Folch extraction was optimized and parallelism tests with spiked samples indicated that the serum matrix did not interfere with mass spectral quantitation. Precision and accuracy of the assay at the lowest limit of quantitation and at low, medium and high levels met with accepted guidelines for single laboratory validation. Several storage conditions that can be encountered with clinical samples also were evaluated for impact on fatty acid levels in serum. Serum from blood that was stored refrigerated for 3 days yielded similar results as serum that was prepared and frozen at -80°C immediately. Serum storage at room temperature for 3-24 hours and serum subjected to one freeze/thaw cycle had minimal effects on fatty acid levels. The intra-individual variability in pregnant women was reasonably small, with significant correlation coefficients ranging from 0.35 to 0.76 for blood drawn between 12-20 weeks versus 34-36 weeks of gestation. These results indicate that GC-MS with single ion monitoring is valid for the analysis of total fatty acids in clinical samples, even when blood processing cannot be performed in a timely manner.

Keywords:

Fatty acids, fatty acid methyl esters, GC-MS, fish oils, pregnancy, blood levels.

Affiliation:

1500 E. Medical Center Drive, Room 2150 Cancer Center, University of Michigan, Ann Arbor, MI 48109-5930, USA.


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Analytical Applications of Flow Injection Chemiluminescence for the Determination of Pharmaceuticals–A Review

Author(s):

Amir Waseem, Mohammad Yaqoob and Abdul NabiPages 363-395 (33)

Abstract:


In this article we present an update on the applications of chemiluminescence coupled with flow injection analysis for the determination of pharmaceuticals. Several reported applications of flow and sequential injection chemiluminescence (FI-CL/SI-CL) in pharmaceuticals concern greatly on quality control, investigation of dissolution of particular formulations or process control of production of pharmaceuticals and their presence in physiological fluids. A number of advances in the development of FI-CL methods have been reported in recent years on pharmaceutical analysis.
In the present review we have covered six years period from Jan-2007 to Dec-2012 discussing FI-CL/SI-CL in the liquid phase as an analytical tool for the determination of pharmaceuticals in diverse samples. We reviewed the methods as per general CL reaction involved with the help of 321 cited references. Interesting features of the FI-CL methods like the use of molecularly imprinting polymers for selectively and specially designed cells/microfluidic devices or lab-on-a-chip for better detection or sensitivity were also presented.

Keywords:

Flow injection analysis, sequential injection, chemiluminescence, pharmaceuticals, biomedical applications, microfluidics.

Affiliation:

Department of Chemistry, Quaid-i-Azam University, Islamabad-45320, Pakistan.


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An UPLC Method for Determination of Geraniin in rat Plasma and its Application to Pharmacokinetic Studies

Author(s):

Zhibiao Yi, Lin Ma, Baoqiang Wang, Wenxuan Cai and Zheng XiangPages 1-5 (5)

Abstract:


Geraniin has many biological activities including anti-osteoporotic and anti-hyperglycemic efficacies. A rapid and simple method for the determination of geraniin in rat plasma using ultra performance liquid chromatography coupled to ultraviolet detector was developed. The plasma sample, spiked with epicatechin as an internal standard, was subjected to ethyl acetate extraction prior to analysis. Chromatographic separation was performed on the HSS T3 column and monitored at a wavelength of 280 nm. The limit of detection and lower limit of quantification was 0.07 μg/mL and 0.2 μg/mL in rat plasma, respectively. Good linearity was obtained in the range of 0.2 - 200 μg/mL, and the correlation coefficient was better than 0.997. The intra-day and inter-day precisions decreased 9.8 %. The accuracy of QC samples ranged from 84.4 % to 87.1 %. The extraction recovery ranged from 88.4 % to 90.3 % and the matrix effect ranged from 84.4 % to 87.2 %. The analyte was stable in rat plasma when stored at room temperature for 12 hours, 4 °C for 24 hours and -20 °C for 15 days. t1/2α and t1/2β for i.v. was 0.21 ± 0.10 and 7.20 ± 2.20 h, respectively. Plasma clearance (CL) was 0.03 ± 0.02 L/h/kg and apparent volume of distribution (Vz) was 0.05 + 0.01 L/kg. The developed method was successfully applied to the pharmacokinetic study of geraniin in rats.

Keywords:

Geraniin, UPLC, pharmacokinetics

Affiliation:

Dongguan Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Dongguan, China.


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Effectiveness and Safety of Digoxin on Chronic Heart Failure

Author(s):

Jia-Lu Yao, Ya-Feng Zhou, Xiang-Jun Yang, Xiao-Dong Qian and Wen-Ping JiangPages 71-79 (9)

Abstract:


Background: The application of digoxin in treating patients with heart failure (HF) has been lasted for more than 200 years, however, controversies remain on the effectiveness and safety of digoxin in prognosis of HF patients. Thus, we performed this meta-analysis of clinical trials that examined the digoxin use to evaluate effectiveness and safety.
Methods and Result: We searched for the cohort studies that investigated the effect of the digoxin on prognosis of the patients with HF in MEDLINE, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and which were published between January 1993 and October 2013. The outcomes of interest comprised all-cause mortality, HF hospitalization and all-cause hospitalization. In addition, pooled hazard risks (HRs) and 95% confidence intervals (CIs) were calculated to assess the effectiveness and safety of digoxin for HF. Nine cohort studies were retrieved from 1431 citation for the analysis, and in total, 84,692 patients were included in the analysis. After synthesizing data, the meta-analysis showed significant increasing of all cause mortality (HR=1.15, 95%CI=1.04-1.27, p<0.001) in the patients with digoxin treatment compared to the controls, whereas no significant difference was found on HF hospitalization (HR=1.06, 95%CI=0.784-1.431, p<0.001) and all cause hospitalization (HR=0.988, 95%CI=0.720-1.354). Moreover, no altered overall results were found after sensitivity analysis.
Conclusion: Therefore, according to the results of our meta-analysis, the use of digoxin could significantly increase the risk of all cause mortality. However, no effect on the HF hospitalization and all-cause hospitalization was found.

Keywords:

Meta-analysis, cohort studies, digoxin, heart failure, mortality, hospitalization.

Affiliation:

Department of Cardiology, the First Affiliated Hospital of Soochow University, Suzhou, 215006, P.R. China.

Graphical Abstract:



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