Analysis of skeletal muscle has potential value in the assessment of cocaine-related deaths

Abstract

This study assesses the interpretive value of cocaine, benzoylecgonine (BZE) and cocaethylene (COET) in skeletal muscle (rectus femoris) in cocaine-using decedents. The distribution of these analytes in cardiac muscle (CM), vitreous humour (VH), femoral blood (FB) and cardiac blood (CB) is also reported. In rectus femoris muscle, the spatial distribution of the analytes was examined across the whole rectus femoris muscle collected from seven fatalities in which cocaine was detected. In six of these cases, death was attributed to trauma and in one case the cause of death was undetermined but suspected to be drug related. In two additional cases analytes were detected in the blood and/or VH but not in the muscle. The muscle was sectioned into 12–15 approximately equal segments, each of which was analysed after homogenisation. Tissue and bio-fluid samples were extracted by solid phase extraction with confirmation and quantification by GC–ion trap-MS/MS. No significant variation was observed in the concentration of any analyte throughout the muscle in the 7 cases analysed. The results reported here are in contrast to a previous study in which great variation in the concentration of some basic drugs (mainly tricyclic antidepressants and benzodiazepines) was observed throughout the thigh muscle bulk (Williams and Pounder, 1997). Analyte concentrations in skeletal muscle (SM) correlated well with those in FB (p<0.01). In general, the concentration of cocaine and COET followed the order VH>CM>SM>FB≥CB. Cocaine concentrations measured in VH were significantly higher than in blood and muscle. Inter-matrix variations in the concentrations of BZE and COET were less marked. The concentration of BZE exceeded that of cocaine in all matrices and in all cases except one where the time between death and drug intake was suspected to be short. In this case, the cocaine to BZE ratio measured in SM (2.66), CM (2.91) and VH (2.19) was higher than that measured in FB (0.97). Given that the concentrations of cocaine and its metabolites were uniformly distributed throughout the muscle and considering the good correlation observed between muscle and blood, muscle could be of interpretive value in cocaine related deaths. Further, since cocaine is known to have greater post-mortem stability in muscle than blood, concentrations measured in muscle may reflect more closely those at the time of death and might be of particular value in cases with an extended period between death and tissue sampling.