LC-MS/MS analysis of Δ9-tetrahydrocannabinolic acid A in serum after protein precipitation using an in-house synthesized deuterated internal standard

2012 ◽  
Vol 47 (6) ◽  
pp. 778-785 ◽  
Author(s):  
Ariane Wohlfarth ◽  
Nadine Roth ◽  
Volker Auwärter
Keyword(s):  
Internal Standard ◽  
Protein Precipitation ◽  
Ms Analysis ◽  
Deuterated Internal Standard

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

Gas chromatographic mass spectrometric determination of myo-inositol in humans utilizing a deuterated internal standard

1982 ◽  
Vol 9 (4) ◽  
pp. 135-140 ◽  
Author(s):  
Jan Rud Andersen ◽  
Elfinn Larsen ◽  
Helge Harbo ◽  
Boye Bertelsen ◽  
J. E. Just Christensen ◽  
...  
Keyword(s):  
Internal Standard ◽  
Mass Spectrometric ◽  
Mass Spectrometric Determination ◽  
Deuterated Internal Standard ◽  
Chromatographic Mass

scholarly journals A Modified Method for Determination of Lumefantrine in Human Plasma by HPLC-UV and Combination of Protein Precipitation and Solid-Phase Extraction: Application to a Pharmacokinetic Study

2010 ◽  
Vol 5 ◽  
pp. ACI.S4431 ◽  
Author(s):  
Liusheng Huang ◽  
Patricia S. Lizak ◽  
Anura L. Jayewardene ◽  
Florence Marzan ◽  
Ming-Na Tina Lee ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Human Plasma ◽  
Solid Phase ◽  
Internal Standard ◽  
Pharmacokinetic Interaction ◽  
Gradient Elution ◽  
Protein Precipitation ◽  
Phase Extraction ◽  
Modified Method

An HPLC-UV method was developed and validated for the determination of lumefantrine in human plasma. Lumefantrine and its internal standard halofantrine were extracted from plasma samples using protein precipitation with acetonitrile (0.2% perchloric acid) followed by solid-phase extraction with Hypersep C8 cartridges. Chromatographic separation was performed on a Zorbax SB-CN HPLC column (3.0 × 150 mm, 3.5 μm) with water/methanol (0.1% TFA) as the mobile phases in a gradient elution mode. Detection was performed using UV/vis detector at λ = 335 nm. The method showed to be linear over a range of 50-10,000 ng/mL with acceptable intra- and inter-day precision and accuracy. The mean recoveries were 88.2% for lumefatrine and 84.5% for the I.S. The internal standard halofantrine is readily available from commercial sources. This method was successfully applied to a pharmacokinetic interaction study between a first-line antimalarial combination (artemether—lumefantrine) and antiretroviral therapy.

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