Toxicokinetic modelling of the synthetic cannabinoid 5F-MDMB-P7AICA and its main metabolite in pigs following pulmonary administration.

Aims: Since their emergence on the drug market, synthetic cannabinoids (SC) are still gaining increasing importance in forensic toxicology. The representatives of the so-called new psychoactive substances have in common that they have not undergone preclinical safety studies. Hence, knowledge on toxicokinetic (TK) data is sparse. As an alternative to human studies not being allowed for ethical reasons, a sophisticated pig model was applied in the present study to assess the TK of the SC 5F-MDMB-P7AICA.

Methods: Pigs pulmonarily received 5F-MDMB-P7AICA via an ultrasonic nebulizer. The parent compound and its main metabolite 5F-MDMB-P7AICA dimethyl butanoic acid were determined in serum and whole blood using liquid chromatography-tandem mass spectrometry. Obtained data was analysed by population (pop) TK modelling. The final pop TK model parameters for pigs were upscaled via allometric scaling techniques for the prediction of human exposure.

Results: The serum concentration-time profiles of the parent and the pop TK analysis revealed that a 4-compartment model best describes the TK data. The administration of the aerosol into the lung compartment follows zero-order kinetics. A transit compartment was further included to accurately describe the time delay between detection of the parent and the metabolite. Despite the different structure, TK parameters were found to be comparable to other examined SC.

Conclusion: The predictions of human SC exposure suggest that multiple administration of 5F-MDMB-P7AICA substantially enhances the window of detection. The simulations pose extrapolation of the data used for model development with respect to dose linearity and allometric scaling to humans.