メタンフェタミン摂取者尿中のｐ‐ヒドロキシメタンフェタミン抱合体濃度およびその加水分解条件の検討

Abstract

The urinary concentrations of the main metabolites of methamphetamine (MA), specifically p-hydroxymethamphetamine-sulfate (p-OHMA-Sul) and p-hydroxymethamphetamine-glucuronide (p-OHMA-Gul) have been directly measured in MA users using an optimized LC-ESI MS method. The concentrations of the main metabolites and unchanged MA in 50 MA users' urine ranged from 0.02 to 21.7 μg/ml for p-OHMA-Sul, from <0.02 to 2.43 μg/ml for p-OHMA-Glu, from <0.005 to 1.33 μg/ml for p-hydroxymethamphetamine (p-OHMA), from 0.01 to 6.79 μg/ml for amphetamine (AP) and from 0.04 to 133 μg/ml for MA, and the ratios of sulfate to glucuronide (S/G ratios) ranged from 2.2 to 37.1 (13.8±8.1). These results demonstrate that the majority of p-OHMA is eliminated as its conjugate and the sulfation is quantitatively more important than glucuronidation for the conjugation of p-OHMA in humans. The urinary concentration time-dependency in two MA users have also revealed that the conjugates were mostly excreted in urine within 3 days post-intake. Both the acid and enzymatic hydrolysis conditions for p-OHMA conjugates were also optimized using the authentic standards of p-OHMA-Sul and p-OHMA-Gul. In the acid hydrolysis, the hydrolysis rate of p-OHMA-Sul was faster than p-OHMA-Glu, and a 3-h incubation with 1.2 mol/l HCl at 98 degrees Celsius gave complete hydrolysis of p-OHMA-Sul and p-OHMA-Glu. On the other hand, the enzymatic hydrolysis of two conjugates with Sulfatase Type H-1 from Helix pomatia required 6 hours for completion.