THE EFFECT OF POSTMORTEM INTERVAL ON THE CONCENTRATIONS OF COCAINE AND COCAETHYLENE IN BLOOD AND TISSUES - AN EXPERIMENT USING RATS

Cocaine and cocaethylene concentrations in blood and tissues at early stages postmortem (0-6 h) were investigated using alcohol-treated rats . Gas chromatography/mass spectrometry following a liquid/liquid extra ction procedure was employed to detect these drugs. Calibration curves showed good linearity in the range of 0 to 2,500 ng/mL with correlati on coefficients of 0.9999 and 0.9998 for cocaine and cocaethylene, res pectively. In a group treated with cocaine and ethanol orally, the liv er lost over 25% of the cocaine present at death after 1 h. Conversely , the hepatic cocaethylene concentrations at this time reached more th an twice those at death. Thereafter, the hepatic concentrations of coc aine and cocaethylene were maintained at a constant level until 6 h po stmortem. Similar results were obtained with rats given cocaine intram uscularly. No changes in the cocaine and cocaethylene concentrations i n any other tissues during the 6-h of postmortem period were observed. The forensic pathologist and toxicologist should be aware of these ph enomena when selecting postmortem specimens for the analysis of cocain e and cocaethylene and take them into account when interpreting the re sults.