Comparison of Oxycodone in Vitreous Humor and Blood Using EMIT(R) Screening and Gas Chromatographic-Mass Spectrometric Quantitation

Abstract

Vitreous humor may serve as a useful alternative specimen for oxycodone analysis in death investigations where blood samples are not available or are of poor quality or limited quantity. The purpose of this study was to investigate the relationship between immunoassay results and gas chromatography-mass spectrometry (GC-MS) quantitation of oxycodone in postmortem vitreous humor and blood. When used with vitreous humor calibrators, the Microgenics DRI Oxycodone (EMIT) Assay was found to be linear from 25 to 500 ng/mL with an limit of detection of 25 ng/mL. Vitreous humor and postmortem blood precipitate immunoassay responses in 57 oxycodone-positive cases were found to be correlated (r(2) = 0.69, p < 0.01). Confirmation and quantitation of oxycodone in vitreous humor by GC-MS was linear from 50 to 1000 ng/mL with a limit of detection of 10 ng/mL and a limit of quantitation of 50 ng/mL. In 30 cases, oxycodone vitreous humor concentrations ranged from less than 50 to 945 ng/mL, and blood concentrations ranged from 103 to 768 ng/mL. The average vitreous humor/blood ratio was 1.16 and ranged from 0.12 to 3.26. Disparities between vitreous fluid and blood oxycodone concentrations were seen in a few cases.

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

“…Cox et al [ 270 ] confirmed this qualitative interest for PCP in a series of 26 autopsies. Oxycodone [ 271 ] and phenytoin [ 90 ] were systematically detected in VH when detected in blood in a respective series of 30 and 12 cases.…”

“…The authors suggested that codeine’s greater lipophilicity might account for higher VH concentrations than blood concentrations, unlike with morphine (logP codeine = 1.39; morphine = 0.87). Knittel et al [ 271 ] reported that oxycodone showed a positive linear correlation between VH and blood concentrations, but with too great a scatter for extrapolation of levels from VH to blood.…”

A Novel Bioanalytical Method for the Determination of Opioids in Blood and Pericardial Fluid

“…The use of microwave-assisted derivatization for the determination of drugs of abuse by GC-MS has already been published (29, zations. Thus, we present a fast microwave-assisted derivatization procedure using hydroxylamine with a reaction time of just 30 s, much shorter than found in other publications: 15 min (34,35,37,39,40,45), 20 min (47), 30 min (36,44,46), 60 min (30,31,33,38,42,43) or 120 min (41). A final fast microwave-assisted derivatization using n-methyl-n-(trimethylsilyl) trifluoroacetamide (MSTFA) + 5% trimethylchlorosilane (TMCS), requiring only 100 s instead of the 15-20 min (31, 33, 36, 39-42, 45, 47), 30 min (30,37,44) or 60 min (38) spent in other published studies, was also described.…”

“…This multiple derivatization is due to the tautomerization that will permit the formation of products from the enol isomer and from the unreacted keto isomer. It must be highlighted that the addition of hydroxylamine does not affect the other opioids [codeine, morphine, 6-MAM, 6-acetylcodeine (6-ACCOD) and fentanyl] since their structures do not have a functional ketone group (30,31,33,(35)(36)(37)(38)(39)(40)(41)(42). There are also studies that used methoxylamine (30,34,35,(43)(44)(45)(46)(47) as derivatization reagent.…”

Silver nanoparticle on zinc oxide array for label-free detection of opioids through surface-enhanced raman spectroscopy

“…For opioid substance detection, there are two existing commercially available techniques, namely the immunoassays and gas chromatography-mass spectrometry (GC-MS). 2,3 The working mechanism of the immunoassay method is to utilize the change in enzyme activity when a specic antibody binds the drug, and the enzyme activity is measured using spectrophotometry. However, most immunoassays have a poor reaction to opiate substances like oxycodone and oxymorphone and may lead to false-negative results.…”