Morphine extraction in necrophagous insects remains for determining ante-mortem opiate intoxication

To study the potential use of insects remains as toxicological indicators, we measured morphine in desiccated entomological materials using a radioimmunoassay method (Coat-A-Count Serum Morphine, Dade Behring, France) following enzymatic hydrolysis. First, enzymatic cuticle extraction of morphine (pronase digestion preceded by a 2 h incubation with a dithiothreitol solution) was performed on various substrates (Calliphoridae puparial cases and desiccated adults, and desiccated pupae of Dermestidae) which were then tested to identify possible interferences with the radioimmunoassay procedure. This same procedure was performed on puparial cases and desiccated adults of Lucilia sericata (Diptera, Calliphoridae) previously reared on minced meat containing various morphine concentrations. Morphine was detected only in cuticle powder from insects reared on meats containing 100 and 1000 mg/kg. Higher concentrations were measured in puparial cases. Rearings on psoas from eight heroin overdose victims confirmed previous experimental results. Remains of necrophagous insects, particularly puparial cases, are often preserved for a long time, and consequently can serve as late alternative specimens for toxicological analysis when suitable tissues are not available. (C) 2001 Published by Elsevier Science Ireland Ltd.