Novel Evaluation of Submandibular Salivary Gland Tissue for Use as an Alternative Postmortem Toxicology Specimen

Abstract

The collection of blood and tissue provides an opportunity for an objective comparison of autopsy results. Occasionally, a viable tissue sample is not available during autopsy. Expanding upon collected tissues to include a tissue that is accessible, is a possible drug depot, and is amendable to various analytical techniques may complement information obtained from other specimens. Given its absorption of ions, nutrients, and likely drugs via its rich blood supply, we evaluated the use of submandibular salivary gland tissue as an alternative postmortem specimen. The submandibular salivary glands of 52 decedents were excised. The tissue was homogenized, extracted, and analyzed via liquid chromatography tandem mass spectrometry for 43 opioids and 5 nonopioids. Liquid chromatography tandem mass spectrometry salivary tissue results were compared with the decedent's blood results. Results revealed that opioids were detected in salivary gland tissue at a sensitivity and specificity of 94.4% and 94.1%, respectively. Nonopioid drugs were detected at a sensitivity and specificity of 88.2% and 100.0%, respectively. This study suggests a comparable correlation exists between salivary gland tissue and blood results for certain drugs. Further evaluation is warranted. To our knowledge, this is the first report of salivary gland tissue being used for postmortem toxicology testing in humans.

Oral Cavity Fluid as an Alternative Postmortem Matrix

“…Also, in the case of the stillborn, the OCF specimen was observed to have morphine at a concentration of 41 ng/mL, the cavity blood had a concentration of 101 ng/mL, and the urinary bladder wash had a concentration of 13 ng/mL. In death investigations of infants, the volume of sample in each specimen is often limited, thus necessitating the sampling of body cavity blood and bladder wash. 42 The OCF specimen allows for a corroborating specimen when other fluids are only available in smaller volumes or not available (eg, exsanguinations). The OCF specimens were equally effective for detection of drugs or metabolites as the blood and urine matrices for these 4 cases.…”

“…Because comparisons of these matrices, OCF and blood, rely on samples from forensic death investigations, the time of dose and the time since death cannot be a controlled variable. The oral cavity is unique with its own microbiome, and little is known of the postmortem conditions of the oral cavity after death 42,44 . The salivary glands may be less likely to be impacted by postmortem redistribution, but the oral cavity is susceptible to the potentials of residual drugs in the submucosa that can remain depending on the route of drug administration 37,42,45–47 .…”

“…The oral cavity is unique with its own microbiome, and little is known of the postmortem conditions of the oral cavity after death. 42,44 The salivary glands may be less likely to be impacted by postmortem redistribution, but the oral cavity is susceptible to the potentials of residual drugs in the submucosa that can remain depending on the route of drug administration. 37,42,[45][46][47] Passive diffusion of the unbound drug from blood is the mechanism responsible for accumulation of analytes in the oral fluid.…”

“…42,44 The salivary glands may be less likely to be impacted by postmortem redistribution, but the oral cavity is susceptible to the potentials of residual drugs in the submucosa that can remain depending on the route of drug administration. 37,42,[45][46][47] Passive diffusion of the unbound drug from blood is the mechanism responsible for accumulation of analytes in the oral fluid. 12,32 It should be noted that after smoking, insufflation, and sublingual or oral drug use, the initial drug concentrations found in oral fluid can be artificially higher than blood concentrations.…”