An Investigation of the Relationship Between Antemortem and Postmortem Drug Concentrations in Blood

Authors

Samantha S. Tolliver, Florida International UniversityFollow

Document Type

Dissertation

Major/Program

Chemistry

First Advisor's Name

Kenneth Furton

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Yong Cai

Third Advisor's Name

W. Lee Hearn

Fourth Advisor's Name

Bruce McCord

Fifth Advisor's Name

DeEtta Mills

Keywords

Postmortem Toxicology, Postmortem Redistribution, Postmortem Blood, Antemortem Blood

Date of Defense

7-8-2010

Abstract

In the field of postmortem toxicology, principles from pharmacology and toxicology are combined in order to determine if exogenous substances contributed to ones death. In order to make this determination postmortem and (whenever available) antemortem blood samples may be analyzed. This project focused on evaluating the relationship between postmortem and antemortem blood drug levels, in order to better define an interpretive framework for postmortem toxicology. To do this, it was imperative to evaluate the differences in antemortem and postmortem drug concentrations, determine the role microbial activity and evaluate drug stability. Microbial studies determined that the bacteria Escherichia coli and Pseudomonas aeruginosa could use the carbon structures of drugs as a source of food. This would suggest prior to sample collection, microbial activity could potentially affect drug levels. This process however would stop before toxicologic evaluation, as at autopsy blood samples are stored in tubes containing the antimicrobial agent sodium fluoride. Analysis of preserved blood determined that under the current storage conditions sodium fluoride effectively inhibited microbial growth. Nonetheless, in many instances inconsistent drug concentrations were identified. When comparing antemortem to postmortem results, diphenhydramine, morphine, codeine and methadone, all showed significantly increased postmortem drug levels. In many instances, increased postmortem concentrations correlated with extended postmortem intervals. Other drugs, such as alprazolam, were likely to have concentration discrepancies when short antemortem to death intervals were coupled with extended postmortem intervals. While still others, such as midazolam followed the expected pattern of metabolism and elimination, which often resulted in decreased postmortem concentrations. The importance of drug stability was displayed when reviewing the clonazepam/ 7-aminoclonazepam data, as the parent drug commonly converted to its metabolite even when stored in the presence of a preservative. In instances of decreasing postmortem drug concentrations the effect of refrigerated storage could not be ruled out. A stability experiment, which contained codeine, produced data that indicated concentrations could continue to decline under the current storage conditions. The cumulative data gathered for this experiment was used to identify concentration trends, which subsequently aided in the development of interpretive considerations for the specific analytes examined in the study.

Identifier

FI10120802

Recommended Citation

Tolliver, Samantha S., "An Investigation of the Relationship Between Antemortem and Postmortem Drug Concentrations in Blood" (2010). FIU Electronic Theses and Dissertations. 321.
https://digitalcommons.fiu.edu/etd/321