A comparison of vitreous fluid and blood matrices in postmortem drug analysis.

Peripheral blood is considered the gold standard for postmortem toxicological analysis. However, vitreous fluid (VIT) has been described as more resistant to postmortem redistribution and may act as an isolated matrix, preserving postmortem drug concentrations. To determine the utility of VIT analysis compared to traditional blood analysis for 6-acetylmorphine, morphine, cocaine, benzoylecgonine, fentanyl, and norfentanyl, paired peripheral blood and VIT were collected and analyzed in 122 postmortem cases from Western Pennsylvania. In this study, we tested the frequency of detection and performed analyses to correlate drug concentrations in both matrices. We demonstrate that VIT provides a viable matrix for the postmortem analysis of several drugs of abuse and their metabolites. However, when both matrices are available for analysis, VIT, when compared to whole blood, is not optimal for all analytes. These differences are likely due to differences in physiochemical properties and other pharmacokinetic parameters.