Technical Services

Drug Metabolism Evaluation Technical Services

I. Model Overview

Drug metabolism refers to the biochemical transformation of drugs within an organism, ultimately converting them into metabolites for excretion. It is a critical process governing drug efficacy, toxicity, and elimination. While the liver is the primary site of drug metabolism, other tissues (e.g., intestine, kidney, lungs) may also contribute. Metabolism modifies drugs into more excretable forms while altering their pharmacological activity or toxicity. Key metabolic sites include:

• Liver: Rich in metabolic enzymes (e.g., CYP450, UGTs).

• Intestine: Involves gut microbiota and enterocytes.

• Kidney/Lungs: Participate in specific metabolic pathways.

1. Metabolic Pathways of Small-Molecule Compounds

Small-molecule drugs primarily undergo Phase I and Phase II metabolism:

• Phase I Metabolism:

• Oxidation, reduction, or hydrolysis to increase polarity (e.g., acetaminophen → N-acetyl-p-benzoquinone imine [NAPQI] via CYP450).

• Phase II Metabolism:

• Conjugation (e.g., glucuronidation, sulfation, glutathione conjugation) to enhance excretion (e.g., morphine → morphine-3-glucuronide).

• Metabolite Identification:

• Techniques: LC-MS/MS, NMR.

• Assess metabolite bioactivity/toxicity.

• Metabolizing Enzyme Profiling:

• Identify key enzymes (e.g., CYP450, UGTs) and evaluate genetic polymorphisms.

2. Metabolic Pathways of Small Nucleic Acid Drugs

Small nucleic acid drugs (e.g., siRNA, ASO) are metabolized via distinct mechanisms:

• Degradation Pathways:

• Cleaved by nucleases (e.g., RNase H, exonucleases) into short fragments → mononucleotides (e.g., siRNA degradation).

• Metabolite Identification:

• Techniques: LC-MS/MS, gel electrophoresis.

• Metabolite Kinetics:

• In vitro models (plasma, hepatocytes) and in vivo animal studies.

• Metabolizing Enzyme Profiling:

• Identify nucleases/phosphatases and assess their activity.

II. Detection Models

1. Primary Hepatocytes

• Species: Human, monkey, dog, rat, mouse.

• Applications:

• Simulate in vivo metabolism to evaluate metabolic stability and metabolite profiles.

2. S9 Fraction & Liver Microsomes

• Liver Microsomes:

• Phase I metabolism studies (oxidation, reduction, hydrolysis).

• Metabolite identification via LC-MS/MS.

• Enzyme phenotyping and kinetic studies (t1/2, Clint).

• Derived from endoplasmic reticulum membranes, rich in Phase I enzymes (CYP450) and limited Phase II enzymes (UGTs, STs).

• Applications:

• Liver S9 Fraction:

• Complex metabolite profiling (non-CYP pathways).

• Enzyme activity assessment (lower activity but broader enzyme coverage).

• Contains both Phase I and Phase II enzymes.

• Applications:

• Key Differences:

• Microsomes: CYP-dependent metabolism.

• S9: Non-CYP or multi-phase metabolism.

• Enzyme Activity: Microsomes (higher for Phase I) vs. S9 (lower but comprehensive).

• Use Cases:

3. Lysosomes

1. Drug Development & Targeted Therapy:

• Lysosome-Targeted Drugs: Exploit acidic environments/enzymes (e.g., Polyphyllin D targeting SMPD1 to induce lysosomal membrane permeabilization [LMP] in HCC).

• Overcoming Drug Resistance: Disrupt lysosomal drug sequestration (e.g., reversing sorafenib resistance).

2. Protein Degradation Technologies:

• CMA Chimeras: Degrade targets via chaperone-mediated autophagy.

3. Metabolic Research & Disease Models:

• Study lysosomal enzyme activity (e.g., density gradient ultracentrifugation, mass spectrometry).

• Model diseases linked to lysosomal dysfunction (e.g., neurodegenerative disorders, cancer).

4. Drug Metabolism & Stability:

• Assess lysosomal hydrolysis pathways (e.g., ophthalmic drug optimization).

5. Autophagy & Cell Death Regulation:

• Induce lysosome-dependent autophagy or LMP-mediated cell death for cancer therapy.

III. Detection Conditions

LC-MS/MS System

IV. Service Credentials, Facilities, and Team

• GMP-Compliant BSL-2 Lab:

• Registered with the National Health Commission for handling HBV, lentiviruses, and human/animal samples.

• Advanced Equipment (Total value: RMB 20+ million):

• Confocal microscope, FACS, ultracentrifuges, qPCR systems.

• Expert Team:

• Ph.D., Wuhan Institute of Virology, CAS.

• 14+ years in liver research.

• Principal investigator for 7 national/provincial grants (NSFC, Guangdong DST, Shenzhen STIC).

• 10+ first/corresponding-author SCI papers.

• Led by AIMBE Fellow, National Young Thousand Talents, and Shenzhen High-Level Talent Awardees.

• Dr. Ming Zhou

V. Case Studies

Case 1: A Shanghai-Based Biopharma Company

Case 2: A Hangzhou Research Institute