The role of alternative specimens in toxicological analysis

Abstract

The use of alternative specimens in the field of toxicology was first described in 1979, when hair analysis was used to document chronic drug exposure. Since then, the use of these 'alternative' samples has gained tremendous importance in forensic toxicology, as well as in clinic toxicology, doping control and workplace drug testing. It is not surprising, therefore, that a large number of papers dealing with the determination of several classes of drugs in saliva, sweat, meconium and hair have been published ever since, owing to the fact that chromatographic equipment is becoming more and more sensitive, mass spectrometry (and tandem mass spectrometry) being the most widely used analytical tool, combined with gas or liquid chromatography. 'Alternative' specimens present a number of advantages over the 'traditional' samples normally used in toxicology (e.g. blood, urine and tissues), namely the fact that their collection is not invasive, their adulteration is difficult, and they may allow increased windows of detection for certain drugs. The main disadvantage of this kind of samples is that drugs are present in very low concentrations, and therefore high-sensitivity techniques are required to accomplish the analysis. This paper reviews a series of publications on the use of alternative specimens, with special focus on the main analytical and chromatographic problems that these samples present, as well on their advantages and disadvantages over traditional samples in documenting drug exposure.

Correlation Between Methylphenidate and Ritalinic Acid Concentrations in Oral Fluid and Plasma

“…Hence, the use of alternative biological matrices should be considered for noninvasive assessment of drug use. Testing of oral fluid has been used successfully as an alternate to blood testing for psychotropic drugs in therapeutic drug monitoring (1 ), pharmacokinetic studies (2)(3)(4), and the detection of drug misuse (5,6 ). Specifically, weak basic drugs such as amphetamine derivatives have been reported to concentrate in oral fluid because their pH is slightly acidic compared with that of plasma (3,7 ).…”

Bioanalytical methods for the determination of synthetic cannabinoids and metabolites in biological specimens

“…Hair testing provides long-term histories via segmental analysis, because hair offers a larger detection window when compared with all the other types of specimens (up to months) [125]. Another advantage of hair as a sample is low potential for donor manipulation.…”

Designer drugs: aspectos analíticos e biológicos

“…106,107 Apesar dos problemas analíticos que técnicas de cromatografia líquida apresentam, estas são técnicas de escolha em análise de matrizes alternativas devido à sua alta sensibilidade, que é crucial considerando-se a baixa quantidade de amostra geralmente disponível nessas situações. 108 Ainda, o cabelo fornece vantagens como facilidade na obtenção, coleta não invasiva, maior dificuldade para adulteração, janela de detecção ampla (Figura 8), além de raramente requerer cuidados no transporte e no armazenamento, o que favorece a estabilidade dos analitos. 2,98,109 A verificação do uso de drogas de abuso por análise de cabelo é uma ferramenta útil para demonstrar ou excluir a suspeita de uso crônico.…”

“…Este é o caso da análise do tecido e sangue do cordão umbilical, e do líquido amniótico, que podem ser utilizados para documentar a exposição à droga no útero. 108 A exposição pré-natal da droga é frequentemente determinada pelo relato materno ou pela análise toxicológica materna e/ou neonatal de fluidos biológicos e de tecidos. O mecônio é o primeiro material fecal do recém-nascido e é frequentemente analisado para determinar a exposição de drogas no período gestacional, devido à sua grande janela de detecção de drogas.…”