Gamma-hydroxybutyric acid stability and formation in blood and urine

Beránková, Kateřina; Mutnanská, Katerina; Balı́ková, Marie

doi:10.1016/j.forsciint.2006.01.017

Cited by 69 publications

(47 citation statements)

References 22 publications

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“…The concentrations are measured at selected time intervals and compared to detect any trend regarding degradation [29][30][31][32][33][34][35][36][37][38][39][40]. Among reported investigations, also studies on authentic material from volunteers dosed with the drug or from laboratory cases have been performed [33,[40][41][42][43][44].…”

Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

“…Stability investigations have been evaluated in several different ways by statistical parametric tests like Student's t-test [34] paired t-tests [40,43], analysis of variance (ANOVA) [36,44] or by nonparametric tests like Kruskal-Wallis and Mann-Whitney [39]. Analytes have been regarded as stable if difference between initial concentration (C 0 ) and concentration at a given time (C t ) does not exceeded the critical difference, d=C 0 -C t <SD of the method of analysis [38,42].…”

Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

“…Analytes have been regarded as stable if difference between initial concentration (C 0 ) and concentration at a given time (C t ) does not exceeded the critical difference, d=C 0 -C t <SD of the method of analysis [38,42]. Stability has also been evaluated on a percentage base with regard to analyte decrease or increase during storage [30,31,37,41,44].…”

Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Zopiclone degradation in biological samples : Characteristics and consequences in forensic toxicology

Nilsson¹

2014

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Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

Section: Design and Evaluation Of Stability Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Zopiclone degradation in biological samples : Characteristics and consequences in forensic toxicology

Nilsson¹

2014

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“…Moreover, no extraction step is necessary as DBS can be directly derivatized, minimizing the sample preparation and reducing the sample turnaround time. Besides the advantages of a rapid collection, also storage of whole blood samples as DBS may be of interest as this may avoid in vitro formation of GHB, which has previously been reported [35,42]. Finally, even though DBS analyses are most commonly performed using LC-MS/MS, we opted to use GC-MS for several reasons.…”

Section: Troductiomentioning

confidence: 99%

“…The stability of GHB in DBS was thoroughly investigated as previous studies reported an increase in GHB concentration during preservation of blood samples withdrawn on certain anti-coagulants [35,42]. So, to investigate the short-term stability of GHB in DBS samples on Whatman 903 filter paper, we evaluated low and high concentration levels (n=3) at different preservation temperatures (room temperature, 4 and -20 °C).…”

Section: Stabilitymentioning

confidence: 99%

Determination of gamma-hydroxybutyric acid in dried blood spots using a simple GC-MS method with direct “on spot” derivatization

2010

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Postmortem Toxicology: Artifacts

Skopp

2009

Wiley Encyclopedia of Forensic Science

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Artifacts (misleading signs) are an inherent part of postmortem toxicology that needs to be assessed and managed, if possible. It is essential to be aware of and be able to identify artifcts. This review attempts to highlight the more important ones as far as known. There are several unique challenges with specimens collected for postmortem toxicology investigation. A major issue is a determination that includes an understanding of the drug use in the immediate antemortem setting and of the medical history contributing to pharmacokinetic variability. Analytical results may be biased by clandestine manufacture of drugs, treatment during resuscitation or hospitalization, as well as by the presence of tolerance. Drug concentration is likely to change already during the prefinal phase. The potential for postmortem alterations must be considered for all but a few drugs. They are likely to depend on a number of variables, including the drug's physicochemical and pharmacokinetic properties, and environmental conditions. The extent of these changes varies significantly between drugs. The phenomenon of postmortem redistribution can result in anatomical site differences as well as in changes over time. Body fluids and tissues as well as drugs present in these specimens are severely affected by autolysis (cell disruption) and putrefaction. As a result, degradation as well as formation of new entities as competing processes to postmortem redistribution occurs. Analysis of formalin‐fixed or embalmed samples may create problems with regard to the isolation of a drug along with a substantial loss, decomposition, or methylation of compounds. The main collection artifact is contamination. An appreciation of how contaminants may be introduced is important. Poor sampling will severely affect a case investigation. The use of appropriate specimen containers and preservatives can be critical with regard to ultimately identify a substance in an individual specimen. Fluoride preservation of blood is recommended for ethanol, cocaine, carbon monoxide, and cyanide. Addition of fluoride can, for example, inhibit neoformation of ethanol, whereas degradation of cocaine is only slowed. Precaution taken to preserve drug stability during storage until analysis is largely guided by the current knowledge on degradation mechanisms operating in a particular matrix. Problems may also occur during isolation and identification of a drug. Determination of the parent drug along with major metabolites and potential degradation products seems necessary to avoid misinterpretation.

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Gamma-hydroxybutyric acid stability and formation in blood and urine

Cited by 69 publications

References 22 publications

Zopiclone degradation in biological samples : Characteristics and consequences in forensic toxicology

Zopiclone degradation in biological samples : Characteristics and consequences in forensic toxicology

Determination of gamma-hydroxybutyric acid in dried blood spots using a simple GC-MS method with direct “on spot” derivatization

Postmortem Toxicology: Artifacts

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