Drug glucuronidation assays on human liver microsomes immobilized on microfluidic flow-through reactors

Area of Science:

• Biochemistry
• Pharmacology
• Chemical Engineering

Background:

• UDP-glucuronosyltransferases (UGTs) are crucial enzymes in the liver for metabolizing drugs and endogenous compounds.
• UGT 'latency,' where full activity is only observed after membrane disruption, complicates in vitro drug clearance predictions.
• Current in vitro glucuronidation assays face challenges in accurately reflecting in vivo UGT enzyme activity.

Purpose of the Study:

• To develop and validate a microfluidic reactor system for studying UDP-glucuronosyltransferase (UGT) activity under flow conditions.
• To investigate the impact of flow-through conditions on UGT-mediated drug metabolism and explore the phenomenon of UGT latency.
• To provide a more accurate platform for assessing drug clearance and understanding enzyme kinetics.

Main Methods:

• Immobilization of human liver microsomes within a microfluidic reactor.
• Characterization of the microreactor's performance using model reactions: 8-hydroxyquinoline glucuronidation (multi-UGT) and zidovudine glucuronidation (UGT2B7).
• Investigation of alamethicin and albumin effects to analyze UGT metabolism under flow conditions.

Main Results:

• The microfluidic reactor successfully facilitated the study of UGT-mediated drug clearance under continuous flow.
• Model reactions demonstrated the feasibility of using the system for characterizing UGT activity and kinetics.
• The study provided insights into UGT latency by observing enzyme behavior under flow-through conditions.

Conclusions:

• The developed microfluidic reactor offers a valuable tool for in-depth mechanistic studies of UGT enzymes.
• This system can help overcome the limitations of traditional assays and improve the prediction of drug clearance.
• The findings contribute to a better understanding of UGT latency and its implications for drug metabolism research.