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- Determinação de GHB em Amostras BiológicasPublication . Castro, André Lobo; Reis, Flávio; Teixeira, HelenaApresentação dos parâmetros de Validação Analítica já estudados no desenvolvimento da técnica de determinação de GHB em amostras biológicas (sangue, urina, cabelo). Serão apresentados os estudos preliminares realizados para o desenvolvimento do método analítico e os resultados de validação obtidos até ao momento no estudo e desenvolvimento da técnica analítica, designadamente, extracção em fase sólida (SPE) e Cromatografia Gasosa acoplada a Espectrometria de Massa em tandem (GC/MS-MS).
- GHB Detection in biological samples by GC‐MS‐MS with forensic purposesPublication . Castro, André Lobo; Reis, Flávio; Teixeira, HelenaApresentação dos parâmetros de Validação Analítica já estudados no desenvolvimento da técnica de determinação de GHB em amostras biológicas (sangue, urina, cabelo). Serão apresentados os resultados de validação obtidos até ao momento no estudo e desenvolvimento da técnica analítica para amostras de sangue, designadamente, extração em fase sólida (SPE) e Cromatografia Gasosa acoplada a Espectrometria de Massa em tandem (GC/MS-MS). Serão também apresentados os resultados dos testes de extração efetuados para efeitos de desenvolvimento da técnica analítica para amostras de cabelo, designadamente, extração líquido-líquido e Cromatografia Gasosa acoplada a Espectrometria de Massa em tandem (GC/MS-MS).
- GHB – amostragem e armazenamento de amostras biológicas de interesse com fins forensesPublication . Castro, André Lobo; Dias, Mário; Reis, Flávio; Teixeira, HelenaO Ácido gama-hidroxibutírico (GHB) é um composto endógeno com um historial de utilização clínica desde os anos 1960’s. No entanto, devido aos seus efeitos secundários, foi classificado como uma substância controlada. É uma substância associada ao consumo ilícito para fins recreativos, para aumento forçado de massa muscular por parte de praticantes de culturismo e ainda ao abuso sexual facilitado por substâncias. A interpretação medico-legal de um resultado positivo para GHB está dependente do seu contexto endógeno e do comportamento post-mortem do composto. Neste pressuposto, serão discutidos os valores endógenos de GHB, quer in-vivo, quer post-mortem, e serão sugeridos alguns cuidados no que diz respeito à amostragem e armazenamento das diferentes amostras biológicas passíveis de ser utilizadas em contexto clínico e forense.
- Endogenous GHB concentrations in whole blood postmortem samples as a biomarker for post mortem interval estimation – A set of real cases analysisPublication . Castro, André Lobo; Tarelho, Sónia; Dias, Mário; Reis, Flávio; Teixeira, HelenaGamma-hydroxybutyric acid (GHB) is an endogenous compound which has a story of clinical use and illicit abuse since the 1960’s. Its postmortem behaviour, namely regarding degradation and metabolism, has been increasingly studied to be used as a putative biomarker for post-mortem interval (PMI) estimation. Thus, whole blood post-mortem GHB levels were obtained in thirty two real cases with previous information on death and autopsy data. The samples were treated through sample methanolic precipitation followed by GC-MS/MS analysis (LLOQ=0.1 mg/L). No differences were encountered for the other parameters evaluated, including age [under 44 years-old - 7.87 2.06 mg GHB/L (n=7), 45 to 60 years-old - 6.80 3.67 mg GHB/L (n=13) and over 61 years-old - 5.72 2.39 mg GHB/L (n=12), p0.05], gender [men - 7.79 5.04 mg GHB/L (n=23), women - 6.72 2.60 mg GHB/L (n=9), p=0.273], cause of death [accident - 7.96 ± 2.26 mg GHB/L (n=8), suicide - 6.75 ± 3.22 mg GHB/L (n=7) and unknown/natural death - 5.14 ± 2.96 mg GHB/L (n=17), p0.05] and presence or absence of substances [absence - 6.37 2.61 mg GHB/L, presence - 6.96 3.38 mg GHB/L, p=0.405]. On the other hand, the results obtained suggest that the PMI (until 5 days between death and sampling) influences GHB whole blood concentration, noticed namely between 48 and 72 hours (24 - 48 hours (p=0.893), 48 - 72 hours (p<0.05); 72 - 96 hours (p=0.123). This study brings additional data regarding the usefulness of GHB levels in forensic toxicology, which might be further strengthened with larger, but comparable, studies from other laboratories and institutions in the forensic toxicology context.
- Valores endógenos de GHB em amostras biológicas post-mortem – determinação analítica e avaliação estatísticaPublication . Castro, André Lobo; Tarelho, Sónia; Franco, João Miguel; Reis, Flávio; Teixeira, HelenaO Ácido gama-hidroxibutírico (GHB) é um composto endógeno com um historial de utilização clínica desde os anos 1960’s. No entanto, devido aos seus efeitos secundários, foi classificado como uma substância controlada. É uma substância associada ao consumo ilícito para fins recreativos, para induzir o aumento da massa muscular por parte de praticantes de culturismo e ainda ao abuso sexual facilitado por substâncias. No entanto, a interpretação médico-legal de um resultado positivo para GHB está dependente do seu contexto endógeno e do comportamento post-mortem do composto. Neste pressuposto, serão apresentados os valores de GHB determinados num conjunto de amostras post-mortem de sangue e cabelo, provenientes de casos sem qualquer suspeita de consumo de GHB. Estes valores foram estatisticamente analisados e comparados no sentido de se averiguar eventuais tendências de comportamento do composto em contexto post-mortem. Os resultados apresentados foram baseados no sexo dos indivíduos, faixa etária, diagnóstico diferencial médico-legal e intervalo post-mortem (intervalo entre a data da morte e a data da autópsia). A concentração média total de GHB em sangue foi de 6,7 g/L, com os valores a variarem entre 1,8 g/L e 15,7 g/L. Em termos de idade dos indivíduos, verificou-se uma descida da concentração do composto à medida que a idade aumenta, com uma média de 7,9 g/L para indivíduos com menos de 44 anos, 6,8 g/L para indivíduos com idades compreendidas entre 45 e 60 anos, e 5,7 g/L para o conjunto de indivíduos com idade superior a 60 anos. Relativamente ao diagnóstico diferencial médico-legal, os valores médios variaram entre 8,9 g/L e 5,1 g/L, consoante a causa de morte referenciada, nomeadamente acidente, causa natural ou suicídio. De notar que nenhum dos casos estudados constituía um contexto de homicídio. Finalmente, e considerando o intervalo post-mortem, foram encontrados valores médios que variaram entre 4,57 mg/L com 4 dias de PMI e 8,29 mg/L com 2 dias de PMI.
- Comparison of endogenous GHB concentrations in blood and hair in death cases with emphasis on the post mortem intervalPublication . Castro, André Lobo; Tarelho, Sónia; Dias, Mário; Reis, Flávio; Teixeira, Helena M.Gamma-hydroxybutyric acid (GHB) is an endogenous compound which has a story of clinical use and illicit abuse since the 1960’s. The possibility to use a multi-sample approach of GHB evaluation, including whole blood and hair, to better characterize a forensic toxicology case and evaluate a possible causal association with the death, is an exciting up-to-date issue. In addition, its post-mortem behaviour, namely regarding degradation and metabolism, has been increasingly investigated as a putative biomarker for post-mortem interval (PMI) estimation. Thus, In order to contribute to clarify this specific aspect, whole blood and hair post-mortem GHB levels were evaluated in thirty two real cases with previous information on death and autopsy data. The results obtained suggest that the PMI (until 5 days between death and sampling) influences GHB whole blood concentration, but not GHB levels in hair samples. No differences were encountered for the other parameters evaluated, including age, gender, cause of death and presence or absence of substances. This study brings new insights regarding the usefulness of GHB levels in forensic toxicology, which might be further strengthened with larger, but comparable, studies from other laboratories and institutions in the context of legal medicine.
- Quantification of GHB by SPE and GC-MS-MS in whole blood samples for forensic purposesPublication . Castro, André Lobo; Dias, Mário; Reis, Flávio; Teixeira, HelenaIntroduction: Gamma-Hydroxybutyrate (sodium hydroxybutyrate; sodium oxybutyrate; GHB) is known to be an endogenous, naturally occurring, short-chained fatty acid found in mammalian tissues, with wide distribution and action in several brain areas (hipothalamus, basal ganglia). Although it was first synthesised in 1960, it soon was noticed that it is no more than an endogenous compound. With more than 30 years of clinical use, both in Europe and the U.S.A, its illicit use includes recreational use, muscle building effects in bodybuilders and drug-facilitated sexual abuse. Used as a club drug, alone or mixed with other substances, it´s symptoms mimetize MDMA, ketamine and ehtanol. On the ohter hand, it is also used for drug-facilitated sexual abuse (DFSA) purposes. Aim: In this work, the authors developed and validated an analytical procedure for GHB detection in whole blood (in vivo and post-mortem), for forensic purposes. Material and Methods: The analytical method was developed preparing the samples by a SPE procedure with MCX OASIS® cartridges, followed by derivatization with BSTFA-TMCS (99:1) and instrumental analysis developed by GC-MS-MS in a Triple Quadrupole apparatus (BRUKER). Results and Discussion: The described method shows good fitness for purpose for whole blood samples. The obtained LOD and LOQ were 200 ng/mL, for 100 uL of sample. This increase in sensitivity was obtained due to an optimized SPE procedure and an instrumental technique state-of-the-art. The work range started at 200 ng/mL, far below the suggested cut-off for whole blood samples (5-10 mg/L). These results will allow the possibility to distinguish post-mortem production, endogenous values and external consumption, whenever this diagnosis should be determined, being applicable to forensic purposes.
- A fast and reliable method for GHB quantitation in whole blood by GC–MS/MS (TQD) for forensic purposesPublication . Castro, André Lobo; Tarelho, Sónia; Dias, Mário; Reis, Flávio; Teixeira, Helena M.Gamma-Hydroxybutyric Acid (GHB) is an endogenous compound with a story of clinical use since the 1960’s. However, due to its secondary effects, it has become a controlled substance, entering the illicit market. A fully validated, sensitive and reproducible method for the quantification of GHB by methanolic precipitation and GC-MS/MS (TQD) in whole blood is presented. Using 100 µL of whole blood, obtained results included a LOD and LLOQ of 0.1 mg/L and a recovery of 86% in a working range between 0.1 and 100 mg/L. This method is sensitive and specific to detect the presence of GHB in small amounts of whole blood (both ante-mortem or post-mortem), and is, to the authors’ knowledge, the first GC-MS-MS TQD method that uses different precursor ions and product ions for the identification of GHB and GHB-D6 (internal standard). Hence, this method may be especially useful for the study of endogenous values in this biological sample.
- Gamma-hydroxybutyric acid endogenous production and post-mortem behaviour – The importance of different biological matrices, cut-off reference values, sample collection and storage conditionsPublication . Castro, André Lobo; Dias, Mário; Reis, Flávio; Teixeira, Helena M.Gamma-Hydroxybutyric Acid (GHB) is an endogenous compound with a story of clinical use, since the 1960's. However, due to its secondary effects, it has become a controlled substance, entering the illicit market for recreational and “dance club scene” use, muscle enhancement purposes and drug-facilitated sexual assaults. Its endogenous context can bring some difficulties when interpreting, in a forensic context, the analytical values achieved in biological samples. This manuscript reviewed several crucial aspects related to GHB forensic toxicology evaluation, such as its post-mortem behaviour in biological samples; endogenous production values, whether in in vivo and in post-mortem samples; sampling and storage conditions (including stability tests); and cut-off reference values evaluation for different biological samples, such as whole blood, plasma, serum, urine, saliva, bile, vitreous humour and hair. This revision highlights the need of specific sampling care, storage conditions, and cut-off reference values interpretation in different biological samples, essential for proper practical application in forensic toxicology.