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Title: Stability Study of Six 1,4-Benzodiazepines in Bio-fluids Stored at -20oC
Authors: Mohammad N. Uddin
Victoria F. Samanidou
Ioannis N. Papadoyannis
Keywords: 1,4-benzodiazepines
urine and saliva
solid-phase extraction
Issue Date: 2010
Publisher: Faculty of Science, Chiang Mai University
Citation: Chiang Mai Journal of Science 36, 3 (September 2010), 451-463
Abstract: An approach has been undertaken to study the stability of six 1,4-benzodiazepines; alprazolam, bromazepam, clonazepam, diazepam, flunitrazepam and lorazepam in spiked plasma, urine and saliva samples at defined time intervals. Quantification was carried out using high-performance liquid chromatography equipped with a photodiode-array ultraviolet detector while extraction was performed using SPE. Spiked samples (0.5, 2.0 ng μL-1) were stored at-20oC and analysed at selected times during 180 days for both plasma and urine, and 120 days for saliva. At -20oC, at the end of the observation period decrease was measured around 40% for flunitraepam and clonazepam and around 20% for remaining four benzodiazepines of the original levels. At end of study period for low concentrations (0.5 ng μL-1) all benzodiazepines were though detectable but a clear pattern of breakdown could not be established. Results of stability study through freeze-thaw cycle during seven successive days for spiked samples stored at -20oC were also reported. All analytes were seemed to be completely stable up to five cycles in plasma, urine, and up to three cycles in saliva. Moreover, stability study of all analytes over a period of one year revealed that standard solution in methanol stored at 4oC can be used without any remarkable degradation. The data collected suggest that quantitative results concerning long-term stored samples should be interpreted with caution in forensic cases.
Description: The Chiang Mai Journal of Science is an international English language peer-reviewed journal which is published in open access electronic format 6 times a year in January, March, May, July, September and November by the Faculty of Science, Chiang Mai University. Manuscripts in most areas of science are welcomed except in areas such as agriculture, engineering and medical science which are outside the scope of the Journal. Currently, we focus on manuscripts in biology, chemistry, physics, materials science and environmental science. Papers in mathematics statistics and computer science are also included but should be of an applied nature rather than purely theoretical. Manuscripts describing experiments on humans or animals are required to provide proof that all experiments have been carried out according to the ethical regulations of the respective institutional and/or governmental authorities and this should be clearly stated in the manuscript itself. The Editor reserves the right to reject manuscripts that fail to do so.
ISSN: 2465-3845
Appears in Collections:CMUL: Journal Articles

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