spudgene

Following oral administration of psilocybin, psilocin appears in the plasma within 20 to 30 minutes and maximum concentrations are achieved within 2 to 3 hours of the dose.Reference Brown, Nicholas and Cozzi 15 , Reference Kolaczynska, Liechti and Duthaler16 Conversion of the parent compound to psilocin appears to be highly variable based on the dispersion of Tmax values reported in oral administration studies (see Table 1). Maximum concentrations of psilocin were linearly dependent on dose in the only oral ascending dose study conducted to date.Reference Brown, Nicholas and Cozzi 15 Similarly, area under the plasma concentration time curve (AUC) also increased proportionally to the dose confirming linear pharmacokinetics of psilocin in the dose range 0.3 to 0.6 mg/kg.Reference Brown, Nicholas and Cozzi 15

Psilocin is extensively distributed to the tissues as the apparent volume of distribution exceeds that of total body water.Reference Brown, Nicholas and Cozzi 15 A value of 298 L was determined based on a population pharmacokinetic estimate, assuming a one-compartment model with linear clearance and linear absorption.Reference Brown, Nicholas and Cozzi 15 The model fitted estimate agrees with the volume of distribution calculated from mean published values for AUC and half-life following intravenous administration.Reference Hasler, Bourquin, Brenneisen, Bar and Vollenweider 12 In a study of N = 3 human participants, the mean absolute bioavailability of psilocin was 52.7% (±20.4%) after oral administrationReference Hasler, Bourquin, Brenneisen, Bar and Vollenweider 12 which is similar to values determined following administration of 14C labeled psilocybin to rodents.Reference Passie, Seifert, Schneider and Emrich 18

After oral administration of psilocybin, the apparent terminal elimination half life of psilocin was variable (see Table 1). An overall mean of 3 ± 1.1 hours was determined after ascending oral doses.Reference Brown, Nicholas and Cozzi 15 Values within a similar range were observed after administration of other oral doses suggesting that elimination half-life is not dependent on the dose, that is, metabolism is not saturated within the dose ranges studied.