Drugs in Embalmed Tissues

Abstract

In postmortem forensic toxicology, there are instances when the only specimens available for testing are embalmed tissues. The embalming process infuses formalin throughout the body as a means of preservation. Formalin is prepared by saturating 40% formaldehyde with water. Methanol is added to formalin to act as a stabilizing factor. Formaldehyde is a highly reactive substance and may react with drugs present in tissues by hydrolysis, degradation, or methylation. Formalin-fixed tissues are prepared for toxicological analysis in a similar manner to fresh tissues; both liquid-liquid extraction and solid-phase extraction may be used. Drug concentrations in embalmed specimens may be affected not only by typical processes affecting postmortem concentrations but also by a reaction with formaldehyde. In addition, the introduction of embalming fluid to the body can dilute specimens, resulting in reduced concentrations. As a result, analyte concentrations in embalmed specimens, formalin-fixed tissues, and formalin solutions generally cannot be considered representative of concentrations present at death. However, qualitative information regarding the presence of drugs may be helpful in assigning the cause and manner of death.