Is vitreous humour useful for the interpretation of 3,4-methylenedioxymethamphetamine (MDMA) blood levels? Experimental approach with rabbits.

As drug instability and redistribution are factors known to affect the interpretation of post-mortem blood levels, we questioned whether post-mortem vitreous humour concentrations could be useful as predictors for the MDMA load at the time of death. In a first series of in vivo experiments using rabbits, 3,4-methylenedioxymethamphetamine (MDMA) concentrations in plasma, blood and vitreous humour were studied as a function of time after intravenous (i.v.) administration of MDMA. Equilibration between the vascular compartment and vitreous humour was attained about 1 h after i.v. MDMA administration. In a second series of experiments, the post-mortem stability of MDMA in vitreous humour in relation to ambient temperature was investigated. Post-mortem MDMA concentrations in vitreous humour were closer to the ante-mortem blood levels when compared to cardiac blood samples. These preliminary investigations in the rabbit model indicate that measurements of vitreous humour concentrations could also be of interest for predicting the blood concentration at the time of death in humans.