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| Author(s): |
Rafael Menck de Almeida
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2012-12-07 |
| Examining board members: |
Maurício Yonamine;
José Luiz da Costa;
Daniel Junqueira Dorta;
Vilma Leyton;
Marina Franco Maggi Tavares
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| Advisor: | Maurício Yonamine |
| Abstract | |
Barbiturates are a class of drugs that act as central nervous system depressant and are associated with high numbers of poisoning cases and non-medical use in several countries. In Brazil, phenobarbital is the most related antiepileptic drug involved in intoxication cases. Patients report that \"this drug is a substance with strong action in the brain.\" In fact, barbiturates are highly related to attempted suicide and homicide cases, in which quantification of these substances to correlate with the possible cause of death is necessary. However, postmortem toxicological analyses are difficult to perform and interpret, because the concentration of toxic agents found is quite complex and affected not only by deterioration condition of the body but also by a process known as postmortem redistribution. In general, higher concentrations are found in the blood located in central sites (e.g. heart cavity) compared with the levels found in peripheral vessels (such as the femoral vein). In other cases, the time between death and postmortem examination is enough for some substances that would normally be present in the blood are no longer available in this biological fluid. Besides, there are few reference values for most non-conventional biological samples, making it difficult to interpret the results. The objective of this work was the development and application of methods for identification of barbiturates (butalbital, secobarbital, pentobarbital and phenobarbital) in postmortem samples (heart blood, femoral blood and liver). The analytes were extracted by using liquid-phase micro extraction (LPME) and quantified by gas chromatography-mass spectrometry (GC-MS). After the development and validation, analytical methods were applied in real cases of eleven corpses autopsied by Death Verification Service of São Paulo City (USP-SVO), with suspected of barbiturates involvement. Nine cases were positive for phenobarbital. The mean ratio of blood femoral / cardiac blood was 0.91 with a standard deviation of 0.23. For the correlation liver / femoral blood the average was 1.17 with a standard deviation of 1.29. Barbiturates were chosen as model for this study because the high incidence of cases of acute poisoning with these drugs in Brazil. (AU) | |
| FAPESP's process: | 09/09682-1 - Postmortem redistribution of phenobarbital in human biological tissues |
| Grantee: | Rafael Menck de Almeida |
| Support Opportunities: | Scholarships in Brazil - Doctorate |