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Document Type
Dissertation - University Access Only
Award Date
2015
Degree Name
Doctor of Philosophy (PhD)
Department
Chemistry and Biochemistry
First Advisor
Brian A. Logue
Abstract
Although the current suite of FDA approved antidotes (i.e., sodium nitrite, sodium thiosulfate, and hydroxocobalamin) are effective for treating cyanide poisoning, each antidote individually has major limitations (e.g., large effective dosage or delayed onset of action). To mitigate these current limitations, next-generation cyanide antidotes are being investigated, including sulfanegen and cobinamide (Cbi). Analytical methods capable of detecting these therapeutics individually and simultaneously (for combination therapy) are essential for the development of sulfanegen and Cbi as potential antidotes. Therefore, two liquid chromatography-tandem mass-spectrometry (LC-MS-MS) methods were developed for 1) the analysis of 3-MP (i.e., sulfanegen converts to the active sulfur donor, 3-MP, upon administration into the blood) individually, and 2) the simultaneous analysis of 3-MP and Cbi. Sample preparation of 3-MP for both methods consisted of spiking plasma with an internal standard (13C3-3-MP), precipitation of plasma proteins, and derivatizing with monobromobimane to produce 3-mercaptopyruvate-bimane (3-MPB). Preparation of Cbi involved denaturation of plasma proteins and addition of excess cyanide to produce dicyanocobinamide (Cbi(CN)2) from each Cbi species. The LOD for the 3-MP method was 0.1 μM and the LODs for the 3-MP/Cbi method were 0.5 μM for 3-MP and 0.2 μM for Cbi(CN)2. For the analysis of 3-MP alone, the linear range was 0.5-100 μM. Linear ranges for the simultaneous method were 2-500 μM for 3-MP and 0.5-50 μM for Cbi. Accuracy and precision for the 3-MP method was 100 ± 9% and <7% relative standard deviation (RSD), respectively. The accuracy and precision for the 3-MP with Cbi(CN)2 method were 100 ± 9% and <5.5% RSD for 3-MP. For Cbi(CN)2, the accuracy was 100 ± 13% and <9.5% RSD, respectively. The methods were able to detect 3-MP in rabbits treated with sulfanegen and rats treated with cobinamide. The development of the validated analytical methods for detection of next generation antidotes will facilitate potential FDA approval, and ultimately, use of the therapeutics for cyanide poisoning. To further determine the effectiveness of 3-MP as a cyanide antidote, its pharmacokinetic properties were evaluated in rabbits. Plasma 3-MP concentrations were monitored using liquid chromatography-tandem mass spectrometry following IV administration of sulfanegen to rabbits. Concentrations of 3-MP rapidly increased during sulfanegen administration, indicating rapid absorption and distribution of 3-MP throughout the body. Elimination of 3-MP was also relatively rapid; the calculated halflife of sulfanegen was ~262 mins, which is comparable to current FDA approved cyanide antidotes. A one-compartment model with first-order elimination was used to describe the pharmacokinetic behavior of 3-MP. The results of this study indicate that sulfanegen may be useful to rapidly combat the effects of cyanide poisoning.
Library of Congress Subject Headings
Cyanides Antidotes Liquid chromatography Tandem mass spectrometry
Description
Includes bibliographical references
Format
application/pdf
Number of Pages
109
Publisher
South Dakota State University
Rights
In Copyright - Educational Use Permitted
http://rightsstatements.org/vocab/InC-EDU/1.0/
Recommended Citation
Stutelberg, Michael W., "Liquid Chromatography-tandem Mass Spectrometry of Next-generation Cyanide Antidotes, 3-mercaptopyruvate and Cobinamide, with the Pharmacokinetic Analysis of 3-mercaptopyruvate" (2015). Electronic Theses and Dissertations. 1882.
https://openprairie.sdstate.edu/etd/1882