Chromatographic determination of drugs of abuse in vitreous humor using solid‐phase extraction

Abstract

A simple method is presented for the simultaneous determination of morphine, 6-acetylmorphine, codeine, cocaine, benzoylecgonine, cocaethylene, methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in vitreous humor by high-performance liquid chromatography with photodiode array detector after solid-phase extraction with Oasis® HLB cartridges and dichloromethane as eluent. The chromatographic process was carried out using an XTerra® RP8 column (250 × 4.6 mm i.d., 5 µm particle size) and a mobile phase composed of acetonitrile and pH 6.5 phosphate buffer in gradient mode. A linear response from the detector was obtained within the concentration range of 0.1-4 µg ml(-1) , with correlation coefficients higher than 0.99. The limits of detection were lower than 30 ng ml(-1) for all the drugs studied, the coefficients of variation fluctuated between 0.1 and 12.4%, and the average recoveries were higher than 78% for all the drugs except for EDDP, with a value of 66.4%. Finally, the proposed method was applied to 15 vitreous humor samples coming from individuals who had died from opiate and/or cocaine overdose, showing consumption of cocaine in 14 cases, methadone in five cases and heroin in three cases. Average concentrations of 0.30 µg ml(-1) for morphine, 0.24 µg ml(-1) for 6-acetylmorphine, 0.10 µg ml(-1) for codeine, 0.81 µg ml(-1) for cocaine, 1.26 µg ml(-1) for benzoylecgonine, 0.15 µg ml(-1) for cocaethylene, 0.11 µg ml(-1) for methadone and 0.68 µg ml(-1) for EDDP were obtained.

Vitreous humor analysis for the detection of xenobiotics in forensic toxicology: a review

“…The extraction techniques generally used for blood and other fluids provide cleaner extracts of VH than other matrices. Solid-phase extraction (SPE) is widely used, notably for assaying benzodiazepines [ 99 ], drugs of abuse (e.g., opiates, methadone, cocaine,) [ 100 – 104 ] and paracetamol [ 103 ]. Bévalot et al [ 105 ] described a generic technique, validated on six compounds and assessed for implementation in large-scale screening.…”

“…Unlike more complex postmortem matrices (e.g., blood, tissue), where enhanced selectivity serves to palliate interference, VH, which can be considered a “clean” matrix, benefits fully from the gain in sensitivity. Analysis of cocaine and cocaine derivatives is a good example illustrating the whole range of analytical techniques that have been implemented for VH analysis: gas chromatography/flame ionization detector (GC/FID) [ 104 ], high-performance liquid chromatography/diode array detector (HPLC/DAD) [ 100 , 114 ], GC/mass spectrometry (MS) [ 101 , 117 , 118 ], GC/tandem mass spectrometry (MS–MS) [ 95 ], HPLC/MS–MS [ 119 ], capillary electrophoresis/DAD [ 111 ] and immunoanalysis (cloned enzyme donor immunoassay [ 120 ], enzyme multiplied immunoassay technique [ 59 ]). Few screening techniques seem to have been specifically dedicated to VH analysis.…”

Evaluation and Determination of Tramadol and Methadone in Vitreous Samples With the Aid of Dispersive Liquid-Liquid Microextraction- High Performance Liquid Chromatography

“…In order to evaluate the amount of tramadol and methadone in plasma and fluids in the body and its amount in pharmaceutical compounds, various methods are used [25]. Spectrophotometers [26,27], HPLC [28][29][30], GC/MS [31,32], HPTLC [33], LC-MS [34], LC-MS/MS [35][36][37], capillary electrophoresis [38,39], and electrochemical methods [40,41] can be mentioned.…”

Redistribuição postmortem de antidepressivos e seus produtos de biotransformação em tecidos biológicos humanos

“…Estas alterações nas composições sanguíneas são causadas pela redistribuição postmortem (PELISSIER-ALICOT et al, 2003) (FERNER, 2008 B . 2007;FERNANDEZ et al, 2013). O humor vítreo (HV) compreende 99% de água e o restante 1% é composto de sais, açúcares, fagócitos e de uma rede de colágeno (ANTONIDES et al, 2007).…”

“…A principal via farmacocinética de absorção das drogas na membrana ocular e, consequentemente estas ficarem difundidas no humor vítreo, é através da difusão passiva. Fármacos inalterados e/ou seus produtos de biotransformação somente não ligados às proteínas plasmáticas são capazes de atravessar essa barreira delgada (COX et al, 2007;FERNANDEZ et al, 2013). Consequentemente, as concentrações de substâncias com elevada afinidade para as proteínas plasmáticas serão diminuídas.…”