The Influence of Body Position and Microclimate on Ketamine and Metabolite Distribution in Decomposed Skeletal Remains

Abstract

The influence of body position and microclimate on ketamine (KET) and metabolite distribution in decomposed bone tissue was examined. Rats received 75 mg/kg (i.p.) KET (n = 30) or remained drug-free (controls, n = 4). Following euthanasia, rats were divided into two groups and placed outdoors to decompose in one of the three positions: supine (SUP), prone (PRO) or upright (UPR). One group decomposed in a shaded, wooded microclimate (Site 1) while the other decomposed in an exposed sunlit microclimate with gravel substrate (Site 2), roughly 500 m from Site 1. Following decomposition, bones (lumbar vertebrae, thoracic vertebra, cervical vertebrae, rib, pelvis, femora, tibiae, humeri and scapulae) were collected and sorted for analysis. Clean, ground bones underwent microwave-assisted extraction using acetone : hexane mixture (1 : 1, v/v), followed by solid-phase extraction and analysis using GC-MS. Drug levels, expressed as mass normalized response ratios, were compared across all bone types between body position and microclimates. Bone type was a main effect (P < 0.05) for drug level and drug/metabolite level ratio for all body positions and microclimates examined. Microclimate and body position significantly influenced observed drug levels: higher levels were observed in carcasses decomposing in direct sunlight, where reduced entomological activity led to slowed decomposition.

Analysis of dextromethorphan and dextrorphan in decomposed skeletal tissues by microwave assisted extraction, microplate solid‐phase extraction and gas chromatography‐ mass spectrometry (MAE‐MPSPE‐GCMS)

“…All analyte levels reported in this work are expressed as mass‐normalized response ratios (RR/m), as has been done in various other published studies . The response ratio (RR) is the ratio of analyte peak area to that of the internal standard.…”

“…other published studies. [4,[7][8][9][10][11] The response ratio (RR) is the ratio of analyte peak area to that of the internal standard. Normalization of RR to the mass of bone sampled (i.e., RR/m) accounts variation in the mass of bone sampled.…”

“…Toxicological analysis of bone has been the subject of renewed interest in recent years. [1][2][3][4][5][6][7][8][9][10] The results of studies since 2000 done with both human tissues derived from forensic casework [1][2][3] and animal tissues derived from studies involving controlled drug exposure and post-mortem conditions [4][5][6][7][8][9][10][11][12] have shown that detection of a wide variety of drugs and metabolites is possible, but there remains uncertainty with respect to the interpretive value of quantitative measurements in bone, due to poor correlation of drug levels in bone and those in corresponding blood samples. Furthermore, the use of bone as a substrate for toxicological analysis may be expected to occur primarily in cases involving extensive decomposition, where few or no other conventional sample types are available.…”

Semi‐quantitative analysis of tramadol, dextromethorphan, and metabolites in decomposed skeletal tissues by ultra performance liquid chromatography quadrupole time of flight mass spectrometry

“…The use of bone as a matrix for toxicological analysis has been investigated extensively since 2000. [19][20][21][22][23][24][25][26] These studies, involving both human remains [19][20][21] and animal remains, [22][23][24][25][26] have shown a wide variability in detected drug and metabolite levels across different bone types. Interpretation of toxicological measurements in bone is also complicated by the inability to properly determine analyte recovery from bone tissue.…”

“…In this work, we report the bone analyte levels as mass-normalized response ratios (RR/m), as has been described in a variety of published studies. [21][22][23][24][25] This approach is taken because analyte recovery from solid bone tissue cannot be accurately measured or calibrated for using techniques conventional to forensic toxicology (ie, GC-MS or LC-MS). 3 | RESULTS…”