Volume 42, Issue 3 (May 1997)
Barbiturates and Analgesics in Calliphora vicina Larvae
Calliphora vicina larvae were reared on artificial foodstuffs spiked with a range of concentrations of aspirin (acetylsalicylic acid), sodium salicylate, paracetamol, sodium aminohippurate, amphetamine sulfate, and the barbiturates thiopentone, phenobarbitone, amylobarbitone, barbitone, and brallobarbitone. Larvae were harvested at either day 6, 7, or 8 for analysis of drug content. Paracetamol, aspirin, amylobarbitone, and thiopentone were not detected in larvae fed on foodstuff containing drug concentrations equivalent to those expected in skeletal muscle from fatal human overdoses. Drug concentrations in larvae (expressed as larva: Foodstuff drug ratio) were 12–14% for phenobarbitone, 9–11% for sodium salicylate, 10% for aminohippurate, 18–19% for brallobarbitone, 41% for amphetamine, and 50–67% for barbitone. Amylobarbitone became detectable in larvae fed on higher drug concentrations (larva: Foodstuff drug ratio 2.6–21%). Higher levels of thiopentone and phenobarbitone were lethal to the larvae. Despite sharing similar basic structures, related drugs were each handled very differently by the larvae. We found it impossible to predict, on the basis of chemical structure, which drugs are likely to be detectable in Calliphora vicina larvae and in what ratio to the drug-spiked foodstuff. Drug concentrations in larvae are significantly lower than in their food source and the absence of a drug from feeding larvae does not necessarily imply its absence from the food source.