Abstract
Psilocybin is an active alkaloid found in magic mushrooms (Psilocybe cubensis). It is classified as a Class I Psychoactive Substance due to its psychoactive properties. Recent research has suggested that psilocybin holds potential for treating major depressive disorder. The objective of this study was to develop a physiologically based pharmacokinetic (PBPK) model for psilocybin and its active metabolite, psilocin, in mice, rats, and humans. This model aims to explore the disposition of psilocin within the body, including its distribution to the target organ, the brain. Psilocybin is assumed to undergo complete conversion to psilocin before the latter enters systemic circulation. The PBPK model effectively characterizes the concentration-time profiles under various dosing scenarios and routes of administration in mice, rats, and humans. The human model has the potential for guiding therapeutic strategies and enhancing clinical trial designs for the therapeutic use of psilocybin.