Drug metabolism and disposition: the biological fate of chemicals
May 1, 2013
Xi-Ling Jiang, Hong-Wu Shen, Donald E Mager et al.
29 citations
Coadministration of the MAO-A inhibitor harmaline sharply increases systemic and brain exposure to the designer drug 5-MeO-DMT and its active metabolite bufotenine in mice. The effect is stronger in wild-type mice than in CYP2D6-humanized mice, because CYP2D6 breaks down 5-MeO-DMT into bufotenine. Surprisingly, a higher harmaline dose (15 mg/kg) reduces bufotenine levels, an effect confirmed in vitro as harmaline also inhibits CYP2D6. A unified pharmacokinetic model describing these interactions was developed and may help predict drug interactions at various doses and in different CYP2D6 genotypes.
Drug metabolism and disposition: the biological fate of chemicals
July 1, 2011
Hong-Wu Shen, Xi-Ling Jiang, Ai-Ming Yu
29 citations
The psychedelic drug 5-MeO-DMT shows nonlinear pharmacokinetics in mice: as the dose increases, the drug's concentration in the body rises more than proportionally. After intravenous or intraperitoneal injections of 2, 10, and 20 mg/kg, dose-normalized blood levels were 1.5- to 2.7-fold higher at the two higher doses compared with the lowest dose. The drug also entered the brain, with brain concentrations increasing nonproportionally with dose. A two-compartment model with nonlinear (Michaelis-Menten) elimination and CYP2D6-dependent linear elimination described the data. These results suggest that the risk of intoxication may increase nonproportionally at higher doses.
Drug metabolism and disposition: the biological fate of chemicals
June 1, 2002
Wenjiang Zhang, Yamini Ramamoorthy, Rachel F Tyndale et al.
17 citations
The ibogaine analog 18-methoxycoronaridine (18-MC) is metabolized primarily into 18-hydroxycoronaridine (18-HC) in human liver microsomes. This conversion is mainly catalyzed by the polymorphic enzyme CYP2C19, with a Michaelis constant (K_m) of 1.34 μM and maximum velocity (V_max) of 0.21 nmol/mg/min. Selective inhibition of CYP2C19 reduced 18-HC formation by 65%, and antibodies against CYP2C enzymes inhibited it by 70%. Other cytochrome P450 enzymes showed negligible involvement. The correlation between 18-MC metabolism and S-mephenytoin 4'-hydroxylase activity across five human liver samples further supports CYP2C19's primary role. These results suggest 18-MC could serve as a probe for CYP2C19 activity.
Drug metabolism and disposition: the biological fate of chemicals
April 28, 2025
Jan Thomann, Deborah Rudin, Selina Kraus et al.
4 citations
A liquid chromatography-tandem mass spectrometry method was developed and validated to measure the recreational psychedelic 2C-B and two of its metabolites (BDMPAA and B-2-HMPAA) in human plasma. The method achieved linear ranges of 0.5–100 ng/mL for 2C-B, 2.5–1000 ng/mL for BDMPAA, and 0.5–1000 ng/mL for B-2-HMPAA with high accuracy and precision. Pharmacokinetic analysis used samples from clinical participants who received 30 mg of 2C-B. Key metabolic enzymes included MAO-A, MAO-B, cytosolic enzymes, and CYP2D6. Unlike 2C-B, the metabolites did not activate the serotonin 2A receptor, indicating they do not contribute to the psychedelic effect. The method provides a reliable tool for future clinical studies.