The Detection of Psilocin in Human Urine

Psilocybin, the active compound in psychedelic mushrooms, is rapidly converted to psilocin in the body. Psilocin is then further metabolized into a glucuronide conjugate that can be detected in urine. By using enzymatic hydrolysis to break the conjugate and derivatization to make the molecule suitable for gas chromatography-mass spectrometry (GC/MS), the detection limit for psilocin in urine improved from 200 ng/mL to 10 ng/mL. Testing of real urine samples found psilocin in 6 out of 8 samples, with concentrations ranging from 10 ng/mL to over 200 ng/mL. Without hydrolysis and derivatization, no samples tested positive.

Study at a glance

Abstract

Abstract Pharmacokinetic studies of psilocybin in humans have shown the rapid dephosphorylation of psilocybin to psilocin with further conversion to 4-hydroxy-tryptophole (4HT) and 4-hydroxyindole-3-acetic acid (4HIAA) in plasma. Our study shows that psilocin also undergoes conjugation and can be found in the urine as the psilocin-glucuronide conjugate. Recoveries after enzymatic hydrolysis of the urine with β-glucuronidase (Helix Pomatia or E. Coli) when compared to non-hydrolyzed urine confirmed the presence of the glucuronide. Detection of psilocin from hydrolyzed and extracted samples was optimized for GC/MS by derivatization with MSTFA. The method developed allows for the detection of psilocin in urine with a limit of quantitation of 10 ng/mL, based on 5 mL of spiked urine. Using this method, our laboratory has confirmed the presence of psilocin in 6 out of 8 urine samples, with concentrations ranging from 10 ng/mL to greater than 200 ng/mL. Before implementation of the hydrolysis and derivatization steps, our limit of detection was 200 ng/mL, based on spiked urine standards. No case samples were positive without hydrolysis and derivatization.