Postmortem redistribution of phenobarbital in human biological tissues

• Grant number: 09/09682-1
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): January 01, 2010
• Effective date (End): December 31, 2012
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Mauricio Yonamine
• Grantee: Rafael Menck de Almeida
• Home Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The concentration of toxic agents found in postmortem samples is complex and affected not only by the deteriorating of the body, but also by a process known as postmortem redistribution, which substances are transferred, after death, in areas of high concentration to areas of low concentration. In general, the highest concentrations are found in the blood of central sites, such as blood collected from the heart cavity, compared to peripheral vessels and the femoral vein. In other cases, the time between death and postmortem examination is sufficient for some substances that would be normally present in blood, are no longer available in this biological fluid. Examples include exhumed bodies and suicide cases which have taken days to find the body which was in decomposition process. Thus, when blood samples are not available for collection, the medical examiners have little alternative to collect unconventional tissue samples for toxicological analysis. In such cases, to interpret the results, it is essential the existence of information in the literature. Unfortunately, there is relatively little information about it and needing more studies on this topic. The preset project will study the postmortem redistribution of phenobarbital through biological specimens analysis (blood, vitreous humor, brain, liver and bone marrow) collected from victims of Medical Institute Legal of São Paulo (SP-IML). This drug was chosen due to the incidence of several case of acute intoxication in Brazil. Analytical methods will be developed aiming the detection of these substances in several samples mentioned. Accelerated solvent extraction (ASE) and liquid-phase microextration (LPME) are recent sample preparation techniques that will be used for analysis. The analytes will be identified by gas chromatography/mass spectrometry (GC-MS) and the results will be evaluated based on concentrations found, victim's history and time between death and autopsy (sample collection).